Can you help me solve this theological puzzle over John 1:14?

• The confusion is caused by not realizing the time/tense and order of timeline.
• Malachi is true that God is not man at that time of history but later the Word became flesh. There was a definite time where the Word took flesh in history.
• Noone sees the Father except through Jesus, the same way noone sees the Holy Spirit except through Jesus
• JOHN 14:8-9 Philip said, “Lord, show us the Father and that will be enough for us.” Jesus answered: “Don't you know me, Philip, even after I have been among you.

The OP assert what is factually incorrect when he says:

A Trinitarian who believes Jesus is God has a problem with John 1:18, where it says God has never been seen. (We know Jesus was seen.) Additionally, the Trinitarian who believes God became flesh has a problem with Malachi 3:6 and Numbers 23:19.

Let me expain why:

We observe the clear statement several times in the NT that no human has ever seen God the Father:

• John 1:18 - No one has ever seen God; the only God, who is at the Father’s side, he has made him known.
• John 5:37 - You have never heard His voice nor seen His form
• John 6:46 - No one has seen the Father except the one who is from God; only he has seen the Father. (See also Matt 18:10.)
• 1 John 4:12 - No one has ever seen God; but if we love one another, God remains in us, and His love is perfected in us.
• 1 Tim 1:17 - Now to the King eternal, immortal, invisible, the only God …
• 1 Tim 6:16 - He alone is immortal and dwells in unapproachable light. No one has ever seen Him, nor can anyone see Him.
• Col 1:15 - … the invisible God …
• Ex 33:20 - But He added, “You cannot see My face, for no one can see Me and live.”
• Isa 45:15 - Truly You are a God who hides Himself, O God of Israel, the Saviour.

By contrast, we have many texts saying that people have seen God.

• Isa 64:4 - From ancient times no one has heard, no ear has perceived, no eye has seen any God besides You, who acts on behalf of those who wait for Him.
• Job 42:5 - My ears had heard of You [= the LORD, V1], but now my eyes have seen You.
• Gen 18:1, 10 - Then the LORD appeared to Abraham by the Oaks of Mamre in the heat of the day, while he was sitting at the entrance of his tent. ... Then the LORD said, “I will surely return to you at this time next year, and your wife Sarah will have a son!”
• Gen 32:30 - So Jacob called the place Peniel, saying, “It is because I saw God face to face, and yet my life was spared.”
• Ex 3:5, 6 - “Do not come any closer,” God said. “Take off your sandals, for the place where you are standing is holy ground.” Then He said, “I am the God of your father, the God of Abraham, the God of Isaac, and the God of Jacob.”
• Josh 5:13 - 6:2 - And the LORD said to Joshua, “Behold, I have delivered Jericho into your hand, along with its king and its mighty men of valour.” (V2)
• Judges 6:14 - The LORD turned to him and said, “Go in the strength you have and save Israel from the hand of Midian. Am I not sending you?” [See also V16]
• Eze 1 - the prophet's vision of God; many elements of which are repeated in Rev 4 & 5. Further, we find in Eze 10:4, “the radiance of the glory of the LORD.” And in Heb 1:3, “The Son is the radiance of God’s glory and the exact representation of his being.”
• See also instances of the “Angel of the LORD” clearly being the LORD - Gen 16:7-13, 22:11-17, 32:24-30, 48:16, Ex 3:2-6, 32:34, Num 22:22-35, Josh 5:13-15, Judg 2:1-4, 6:11-23, 13:3-23, Isa 63:9, Dan 3:25, 28, Hos 12:4, 5, Zech 3:1-7, Mal 3:1, Rev 8:3-5, 10:1-10, 18:1, 20:1-4.
• A closely related phrase, “Angel of God” who is clearly God as in Gen 6:13, 8:15, 9:8, 17, 15:13, 17:3, 4, 21:12, 16-21, 35:1, 10, Ex 4:3-8, 6:2, 23:20, 21, Deut 1:6, 1 Kings 12:22, etc. See also Acts 10:3, 4, Gal 4:14.

The very fact that the NT so confidently asserts that no human has seen God the Father, but many people have seen God/YHWH in the OT means the inescapable conclusion is such epiphanies were of the pre-incarnate Jesus as per John 8:58 – “Truly, truly, I tell you,” Jesus declared, “before Abraham was born, I am!”

Contrary to what the OP suggests, John 1:18 is clearing up the very puzzle that the OP discusses by essentially saying something like:

No one has ever seen God the Father, but God the Son has revealed Him (many times and in many ways as per Heb 1:1-3).

Here's one point of view shared by many trinitarians and binitarians.

Numbers 23:19 ("God is not a man …") and Malachi 3:6 ("… I change not …") are not referring to God's physical appearance, but to the consistency of divine personality and character.

God has appeared in various physical forms such as a burning bush (Exodus 3:4), a pillar of fire or cloud (Exodus 13:21), and as a human (Genesis 18:1 (Abraham), and Genesis 32:28 (Jacob)).

Consider John 1:18:

• (NIV) No one has seen God at any time.
  The only begotten Son, who is in the bosom of the Father, He has declared Him.
• (RSV) No one has ever seen God; the only Son, who is in the bosom of the Father, he has made him known.
• (CSB) No one has ever seen God. The one and only Son, who is himself God and is at the Father’s side — he has revealed him.

Here, "God" refers to the Father. Until Jesus revealed the existence of the Father to mankind, no one had ever heard of him, much less seen him.

The YHWH of the Hebrew scriptures wasn't the Father; YHWH was Jesus before his incarnation. God the Father has never been seen. The being known as Jesus was the God that was seen by Abraham, Jacob, Moses, and others.

Jesus makes this claim to be YHWH in John 8:58 for instance:

• (NKJV) Jesus said to them, “Most assuredly, I say to you, before Abraham was, I AM.”
• (NLT) Jesus answered, “I tell you the truth, before Abraham was even born, I AM!
• (HNV) Yeshua said to them, "Most assuredly, I tell you, before Avraham came into existence, I AM."

The Septuagint uses the same Greek words, "ἐγώ εἰμι", for "I AM" in Exodus 3:14, where God tells Moses "I AM WHO I AM".

Upon hearing this blasphemous claim, "they took up stones to throw at Him", so there is no doubt on anyone's part as to what Jesus meant.

There is more detailed and relevant information in "I am" in Greek Septuagint translation of Exodus 3:14 vs. John 8:58 - how do they compare? - Biblical Hermeneutics Stack Exchange.

I'm a Biblical Unitarian, and I don't have a problem with John 1:1, yet I think it's reasonable to hold that 'the Word' = Jesus here.

In fact, I think understanding John 1:1 is key to understanding the entirety of John's Gospel, and it's now one of my favourite verses because it's so important to the entirety of not just the Gospel, but the NT and the Bible.

The biggest clue to understanding John 1:1 is John 20:28, where Thomas says to Jesus "My Lord and my God!"

What does Thomas mean? The previous time Jesus talks to Thomas in John's Gospel, Jesus says "When you see me, you see the Father."

Is this an identity claim? Both non-Unitarians and Unitarians mostly would agree it isn't any kind of straightforward identity claim - modalists would be closer to saying that.

So the question for everyone is "in what sense do you see the Father when you see Jesus?"

The answer is obvious once you see it, and given again and again in the Gospel of John. Jesus is God in the sense of agency.

This not only solves the puzzle, but makes complete sense of John 1:18. You see the agent, who is God in the sense of agency - Jesus has "made the Father known." Indeed, this is compatible with the major textual variants at 1:18.

Consider the words of Jacob:

So Jacob called the name of the place Peniel, saying, “For I have seen God face to face, and yet my life has been delivered.” (Genesis 32:30)

And Paul:

For God, who said, “Let light shine out of darkness,” has shone in our hearts to give the light of the knowledge of the glory of God in the face of Jesus Christ. (2 Corinthians 4:6)

The Bible is filled with verses that say:

• you can't see the face of God and live
• I just saw the face of God and lived

Both are true. There is a totality of God's being that we as finite beings cannot see without being consumed. There are true glimpses of part of God's glory that we can (by grace) see and still live.

God is Spirit, so eyes designed to see material things cannot see that. God is also the Words that He speaks, as John said. That we can "see" with our ears, which then process the concepts and absorb them into ourselves.

Exodus 33 makes it clear that there is a distinction between what can be "seen" of God and what cannot:

17 And the Lord said to Moses, “This very thing that you have spoken I will do, for you have found favor in my sight, and I know you by name.” 18 Moses said, “Please show me your glory.” 19 And he said, “I will make all my goodness pass before you and will proclaim before you my name ‘The Lord.’ And I will be gracious to whom I will be gracious, and will show mercy on whom I will show mercy. 20 But,” he said, “you cannot see my face, for man shall not see me and live.” 21 And the Lord said, “Behold, there is a place by me where you shall stand on the rock, 22 and while my glory passes by I will put you in a cleft of the rock, and I will cover you with my hand until I have passed by. 23 Then I will take away my hand, and you shall see my back, but my face shall not be seen.” (Exodus 33:17-23)

Note that the most important thing that God reveals to Moses is His Name. We can see God's glory verbally, in His Word.

About a decade ago, I reflected on these words of Moses and decided to imitate him. For three years I prayed and fasted one day a week with a single prayer, "Lord, show me your glory." I saw no visions. I had no mysterious dreams. No theophany or Christophany. What did happen was that a few months after my prayer concluded, my thirst for reading the Bible increased dramatically. I began to understand passages that had baffled me for years. I was "seeing" God's glory in His Word. It only becomes glorious when it is understood.

As for Malachi's words that God does not change, they fall in a passage that predicts the coming of the Messiah. And as for the idea that God is not a Son of Man, consider words even older than those of Malachi or Moses:

Then Bildad the Shuhite answered and said:

2 “Dominion and fear are with God;
    he makes peace in his high heaven.
3 Is there any number to his armies?
    Upon whom does his light not arise?
4 How then can man be in the right before God?
    How can he who is born of woman be pure?
5 Behold, even the moon is not bright,
    and the stars are not pure in his eyes;
6 how much less man, who is a maggot,
    and the son of man, who is a worm!” (Job 25:1-6)

Compare these to Job's words:

Even now, behold, my witness is in heaven,
    and he who testifies for me is on high.
20 My friends scorn me;
    my eye pours out tears to God,
21 that he would argue the case of a man with God,
    as a son of man does with his neighbor. (Job 16:19-21)

God said in the end of Job that Job had spoken correctly about God, but the friends had not. The words of Bildad are the final words of the friends' arguments. They deny the incarnation ("born of woman") and the sinlessness of every "Son of Man". The answer to the dilemma was that God had not yet become a Son of Man, but he would. Job was a man of faith calling for a savior who had not yet come. He believed that a "Son of Man" would argue his case before God. The friends were men of sight, speaking of what was known and had happened and could be experienced in their "now". Malachi's and Bildad's words are true in general about all "sons of man" except one, because he was not only human but divine. Thus the words do not apply to Jesus because he is not only a Son of Man.

As for God being unchanging, we know that Jesus was slain before the creation of the world (Revelation 13:8). We must not make of the doctrine of the unchangeableness of God shackles that prevent Him from acting in our world. God created time and change in order to reveal his unchanging glory. That is a truth too big for our philosophies to handle.

Doctor Stephen Olford, a respected preacher who is now with the Lord, once said in a sermon,

"The glory of God is the outshining of His presence."

Did God's glory shine through Jesus Christ, the Word of God? Most assuredly, yes!

In King James English, the sentence that begins with the words "We beheld his glory" tells us that what the apostle John saw was God's glory. That glory was beheld by the eyes of every person who saw Jesus in person.

Jesus's glory stems from his "one and only" status as the "firstborn" Son of God. His uniqueness stems from his being the God-Man, the one in whom all the fullness of Deity resided (Colossians 1:19, and 2:9).

Jesus bore witness to that divine fullness through his words and through the many wonders and signs he gave and the miracles he performed in the presence of those who witnessed his life. In his first letter to believers, John said this:

That which was from the beginning, which we have heard, which we have seen with our eyes, which we have looked at and our hands have touched—this we proclaim concerning the Word of life. 2 The life appeared; we have seen it and testify to it, and we proclaim to you the eternal life, which was with the Father and has appeared to us. 3 We proclaim to you what we have seen and heard, so that you also may have fellowship with us. And our fellowship is with the Father and with his Son, Jesus Christ. 4 We write this to make our[a] joy complete.

In short, the witnesses to Jesus's life did not see God; they did, however, see the glory of God revealed through Jesus in his words and his works. When Jesus said at the grave site of Lazarus, "Lazarus, come forth," the believing witnesses at the grave site saw "the glory of God” (see John 11:40 and Matthew 17:1-3). Martha and the other believers did not see God; they saw God's glory. That glory was the outshining of God's presence that resided in Jesus.

Yes, there is a puzzle, and the key to clearing it up is to understand wherein lies the puzzle. As stated in this book dealing with Christian doctrines:

"The doctrine of the Trinity will always remain a mystery, but thanks to Origen, it can at least be expressed in such a way that we can see wherein the mystery lies." Heresies and Orthodoxy in the History of the Church p.91, Harold O.J. Brown, Baker Book House Co. 1998

John 1:14 sets forth an astonishing fact about "the Word", which gives rise to much debate because - to put it simply - there are two distinct approaches to this verse, and there can be no meeting of minds between the protagonists (for such they are) for as long as they take one or other of the following theological stances:

1. The Word of John 1:1 and 1:14 refers not to God but to what the Word became in v.14 - flesh - a human who walked on earth at a certain point in time. This man was never God because God created him, making this man a creature. "There was a time when he was not", to use wording of those whom Origen disagreed with.

2. The Word of John 1:1 and 1:14 speaks of the deepest mystery of God, revealed in time to humanity as the man Jesus Christ, who had never been created because he was the eternal Word of God who "made everything that was made" (vs. 3) showing that the Word is Creator, not created.

To understand that as the key to the puzzle you mention could lead to understanding this mystery of God a bit better, but for those who insist that "there was a time when [the Word, who became Jesus] was not", nothing anybody says will help them solve this mystery, because for as long as they insist Jesus had a starting point in time, they have effectively thrown the key away.

Of course, you will disagree with that, and I understand why, and I will not enter into debate about it. I'm simply suggesting that the key to solving this mystery lies in discovering just who Jesus Christ is, as to whether he had a starting point in time, or whether he "made everything that was made". It does not lie in thrashing out Bible verses about humans either seeing God or not. That's just one of the knotty threads that has tangled up the mystery more. I suggest that if we cut to the chase and deal with the foundational matter of whether the Word, who became flesh, was ever created, the mystery will head towards resolution. Not completely, this side of eternity, of course, but to the extent that the inspired scriptures would inform us.

The Hard Place assumed in OP does not actually exist.

The Dilemma - "John 1:1 says that "the Word was God." This "Word" is then said in John 1:14 to have become flesh--understood to be Jesus. This is then followed by John 1:18 which says no one has seen God."

There is no dilemma here. What is perceived in verse 14 is glory and that glory is of the only begotten of the Father. This Word (who was God in the beginning) did tabernacle among us. The glory that was seen was the glory that Jesus had with God before the world was and it is the glory of God's own self:

And now, O Father, glorify thou me with thine own self with the glory which I had with thee before the world was. - John 17:5

God has not changed. This is not the first time that God has dwelt among His people nor the first time that God's glory has been seen (Exodus 40, Ezekiel 43, for example). The tabernacle in the wilderness and the temple in Jerusalem were types of what was to come. The flesh of Jesus is that temple made without hands within which all the fullness of God was pleased to dwell, and that, permanently.

There is no opposition here. The only begotten has both seen and declared God because He was both with and was God in the beginning (John 1:1). What was and is seen by believers is glory and that glory is the glory of God:

For God, who commanded the light to shine out of darkness, hath shined in our hearts, to give the light of the knowledge of the glory of God in the face of Jesus Christ. - 2 Corinthians 4:6

There is no scripture which says that God's glory cannot be seen by men. God is Spirit and eyes of flesh cannot see spirit directly. Physical eyes can, however, perceive the activity of spirit as it lives within and animates flesh:

The wind bloweth where it listeth, and thou hearest the sound thereof, but canst not tell whence it cometh, and whither it goeth: so is every one that is born of the Spirit. - John 3:8

So it is with Jesus; All the fullness of eternal God, who is Logos and Spirit, living within and animating a human body which had a beginning in time. The Word of life, which was God (invisible God) in the beginning was seen and handled in flesh and by flesh:

That which was from the beginning, which we have heard, which we have seen with our eyes, which we have looked upon, and our hands have handled, of the Word of life; (For the life was manifested, and we have seen it, and bear witness, and shew unto you that eternal life, which was with the Father, and was manifested unto us;)

Thus physical eyes could be and were expected by Jesus to have seen the Father, who is God and Spirit:

If ye had known me, ye should have known my Father also: and from henceforth ye know him, and have seen him. Philip saith unto him, Lord, shew us the Father, and it sufficeth us. Jesus saith unto him, Have I been so long time with you, and yet hast thou not known me, Philip? he that hath seen me hath seen the Father; and how sayest thou then, Shew us the Father? - John 14:7-9

The "puzzle" is solved if we read the verses you cited carefully in context, instead of treating a verse's sentence as an atomic logical proposition.

First, the 3 OT verses are irrelevant:

• Numbers 23:19: the larger context is Num 22-24 (prophet Balaam hired by King Balak to curse Israel), the immediate context is the LORD's second message (Num 23:18-24) where the LORD said how Israel will be protected against any curse (v. 23) and how the LORD will instead let Israel "rise up like a lioness" until she has defeated her enemies (v. 24). Thus v. 19:

  "God is not a man, so he does not lie. He is not human, so he does not change his mind. Has he ever spoken and failed to act? Has he ever promised and not carried it through?"

  has nothing to do with God's later incarnating in Jesus of Nazareth but about how when God has promised something (v. 23-24) He will deliver and not change His mind like a human "in time" (Christians believe God is the Eternal Now). So a contextual interpretation of this verse is God is a reliable fulfiller of promise, but NOT a logical proposition about God never incarnating into a man.

• 1 Sam 15:29: the context is when Saul pleads to Samuel to intercede for him so that the LORD changes his mind and not take Saul's kingship away from him (1 Sam 15:10-31). V. 29 is similar to Num 23:19 The function of v. 29's "for he is not a man" is similar to Num 23:19: as a rhetorical certainty from Samuel to Saul (who is trying to bargain) by Samuel's appealing to God's character: once He has decreed something, He will certainly carry it through. In this case, Samuel emphasizes that the LORD will certainly remove His anointing from Saul as King. Again, this verse has nothing to do with God later incarnating in Jesus.

• Mal 3:6: the context is Mal 3: a warning of the coming day of judgment (vv. 1-5) but offering a way out in repentance by calling Israel to worship the LORD again in the Temple with tithes and offerings (vv. 6-15), with this promise solemnized in a scroll of remembrance containing the names of those who feared and honored the LORD (vv. 16-18). v. 6-7:

  "I am the LORD, and I do not change. That is why you descendants of Jacob are not already destroyed. Ever since the days of your ancestors, you have scorned my decres and failed to obey them. Now return to me, and I will return to you," says the LORD of Heaven's Armies.

  So the context is the LORD's reminder of his character which He announced in first sentence, reminding us how in Ex 20:2 He preceded the ten commandments with a similar first sentence reminding Israel of his faithfulness. The purpose of v. 6 is a guarantee from the LORD's character that he will continue to preserve a remnant of the righteous despite the 2 exiles. Again, this verse has nothing to do with God later incarnating in Jesus.

Now let's consider John 1:18.

Structurally this is part of the Prologue (John 1:1-18); if we read the entire book, we can sense that the Prologue serves like a book's Introduction containing the thesis statement that will be fleshed out in the books's chapters. The Prologue's purpose is introducing who Jesus was, where Jesus came from, why Jesus came, how people don't recognize Jesus for who he really was, but how for the eyewitness believers of Jesus they have received "one gracious blessing after another" (which includes the right to become children of God, v. 12-13) and have received God's revelation in Jesus.

The immediate context is vv. 16-18: how the believers understood Jesus, and want us to see Jesus the same way. Notice the wording in ESV:

No one has ever seen God; the only God, who is at the Father's side, he has made him known.

which is easier to understand in NLT:

No one has ever seen God. But the unique One, who is himself God, is near to the Father's heart. He has revealed God to us.

From the context of the whole Prologue, the first "he" in "he has made him known" (identified as "the unique One" in the NLT, circling back to the mysterious logos in v. 1) clearly refers to the subject of vv. 2-17: Jesus Christ (v. 17). The main point of v. 18 is that Jesus is the revealer of God, who until Jesus came "no one has ever seen God".

Conclusion

Therefore the "puzzle" is solved if you don't take the phrase "No one has ever seen God" (v. 18a) in isolation as though it is a self-standing logical proposition. Even in the same verse (v. 18b) John is saying that through Jesus Christ God becomes "known" (ESV) / "revealed" (NLT), which in the context of the whole Prologue meant known/revealed in a flesh-and-blood human being Jesus Christ.

• First and foremost, I believe in the Trinity ( The Father, The Son and The Holy Spirit)
• In John 1:1, the Word was "Jesus Christ". No one has ever seen God ... - John 1:18. Yes, no one ever seen God in His form and magnificence. We cannot see God also because He is spirit NOT flesh. In order for the God to be seen to us, He must take a form which can be readily seen and observed such as a human, pillar of fire, pillar of cloud etc)
• Coming to John 1:14, God became flesh and dwelt among us is a compulsory act to be a mediator who can be able to connect humans with God. So Jesus Christ has to be a God-Man who can hold the God (The Father) with one hand and humans with the other. God is not a man that he should lie; neither the son of man that he should change his mind - Numbers 23:19. The word is is a present tense and doesn't imply in anyway in the future that God won't become a human. It's like me saying I am not a pilot that I should know how to fly a plane. This doesn't imply that I can never be a pilot and won't be knowing how to fly a plane. The word lie and repent / change of one's mind are used to make us understand and relate because every human does these acts. One can also say that the word man in the above verse is used for the purpose of relatability not for the pavement to contradiction.
• For I, the LORD, do not change - Malachi 3:6 it is not talking about the form but about the intrinsic nature. We put our trust in the God who doesn't change his nature based on the circumstances. Jesus Christ is the same yesterday,today and forever.- Hebrews 13:8. Based on this verse one won't be posing a question saying, Is Jesus Christ same before the crucifixion vs after the crucifixion ?? The answer is yes and no. Yes, for his intrinsic nature never changes. No, for he has risen with a glorified body but make no mistake, it is His own body which was crucified. Our heavenly or glorified bodies will differ from our earthly ones in type of flesh, in splendor, in power and in longevity.

So I don't see any contradiction between the verses you have mentioned.