What is the Biblical basis for unitarianism?

The article Appendix 10. Jesus is the Son of God; not God the Son (from the Revised English Version, by Spirit & Truth Fellowship International) explores this in depth.

See sections 4. "The New Testament teaches that Jesus was a man," 5. "Jesus was like Adam," 6. "Jesus has a God," 7. "Jesus called God "the only true God"," 8. "Jesus was part of God’s creation," 9. "God is eternal, but Jesus had a beginning," 10. "The Bible teaches that Jesus and God are two distinct beings," 11. "The Bible teaches that the Father is God," 12. "God is greater than Christ," 13. "Major differences between Jesus and God" (including wisdom, knowledge, perfection-growth, temptation, death, family, works - similarly, not unoriginated, not self-existent, not immortal, not all wise, not all-powerful, not omnipresent) and 14. "God is spirit, but Jesus is flesh and bone."

The evidence that NT writers thought Jesus was not God is wide and multi-faceted.

I'd like to offer another answer because I'm pretty sure user14 believes in Arianism. Arianism is considered a form of Unitarianism, but I believe you're asking for biblical evidence that Yeshua is a man, and not "a god" or a preexisting spiritual entity.

Strictly speaking from a soundness perspective, the gospels say Yeshua is a man. Therefore, the only thing we can be absolutely sure of is that Yeshua is a man. This is the reason why the trinitarian formula necessarily says Yeshua is "fully human" and it is why Arianism falls short.

However, trinitarian theology also says Yeshua is God, but there is not a single verse in the NT that says this. Therefore, where soundness in trinitarianism is concerned, Yeshua is definitely a man- but there is supposedly a hidden gnosis that reveals Yeshua to be God. So as you read this, bear in mind that most of it is actually relevant to trinitarianism.

Unscriptural Terms

The following words and phrases are used by trinitarians, as well as many Arians. None of these are in any bible I have ever read:

Trinity

Triune

Three persons

Co-exist

Pre-exist

Co-inherence

Incarnation

Jesus is God

Jesus said "I am God"

God became a man

God died (!!!)

Eternally begotten

Eternal generation

One substance

Homoousion

Plato and Aristotle

There are many other terms, including the Greek philosophy essential to explaining these terms, but I think you get the idea.

The son of man

In all four gospels, Yeshua refers to himself as "the son of the man" or ὁ υἱὸς τοῦ ἀνθρώπου. Matthew, Mark, and Luke are fairly similar in their accounts of Yeshua's life, and in none of these is Yeshua ever presented as anything other than a man. There are two virgin birth stories in Matthew and Luke which sound nothing alike, but even if the first two chapters of these books are legit, Yeshua is a man and understood to be a man.

John's Gospel

When we get to John's gospel, things get a bit "mystical", but John still refers to Yeshua explicitly as a man:

"This is he of whom I said, After me cometh a man which is preferred before me: for he was before me." John 1:30

"John answered and said, A man can receive nothing, except it be given him from heaven." John 3:27

"Come, see a man, which told me all things that ever I did: is not this the Christ?" John 4:29

"Not that any man hath seen the Father, save he which is of God, he hath seen the Father." John 6:46

Book or Acts

The book of Acts also presents Yeshua as a man, as the following verse clearly shows:

"Ye men of Israel, hear these words; Jesus of Nazareth, a man approved of God among you by miracles and wonders and signs, which God did by him in the midst of you, as ye yourselves also know" Acts 2:22

Epistle to the Hebrews

In the epistle to the Hebrews, not only is Yeshua presented as a man, but the author's entire argument rests on this fact. Here is another answer that explains why the Greek word δι' means "because of", even in the genitive. So Hebrews 1:2 says:

"Hath in these last days spoken unto us by [his: not in the Greek] a son, whom he hath appointed heir of all things, by (δι': because of) whom also he made the worlds (ages)."

The ages were not made "by" Yeshua- they were made “because of” him- because he is the reason (logos) for the preparation of man. YHVH is pretty clear about making everything by Himself:

"Thus saith YHVH, thy redeemer, and he that formed thee from the womb, I am YHVH that maketh all things; that stretcheth forth the heavens alone; that spreadeth abroad the earth by myself" Isaiah 44:24

The ages were also not made "through" Yeshua, because that doesn't make any sense. Yeshua was not some sort of "Word-tool" that God used to prepare all things.

The first two chapters of Hebrews is about mankind. The author is arguing that it wasn't angels, or any other divine being, that God made the world for. This is explained in Genesis:

"And God said, Let us make (נַֽעֲשֶׂ֥ה: accomplish; H6213) man in our image, after our likeness: and let them have dominion over the fish of the sea, and over the fowl of the air, and over the cattle, and over all the earth, and over every creeping thing that creepeth upon the earth." Genesis 1:26

This is why the next verse in Hebrews says:

"Who being the brightness of [his] glory, and the express image of his person, and upholding all things by the word of his power, when he had by (δι': because of) himself purged our sins, sat down on the right hand of the Majesty on high; Being made so much better than the angels, as he hath by inheritance obtained a more excellent name than they."

The author then goes goes on to explain how the Scriptures prove that God has always favored mankind. He ends his prologue in the next chapter with verses 5-18:

"For unto the angels hath he not put in subjection the world to come, whereof we speak.

But one in a certain place testified, saying, What is man, that thou art mindful of him? or the son of man, that thou visitest him?

Thou madest him a little lower than the angels; thou crownedst him with glory and honour, and didst set him over the works of thy hands:

Thou hast put all things in subjection under his feet. For in that he put all in subjection under him, he left nothing that is not put under him. But now we see not yet all things put under him.

But we see Jesus, who was made a little lower than the angels for the suffering of death, crowned with glory and honour; that he by the grace of God should taste death for every man.

For it became him, for whom are all things, and by (δι': because of) whom are all things, in bringing many sons unto glory, to make the captain of their salvation perfect through sufferings.

For both he that sanctifieth and they who are sanctified are all of one: for which cause he is not ashamed to call them brethren,

Saying, I will declare thy name unto my brethren, in the midst of the church will I sing praise unto thee.

And again, I will put my trust in him. And again, Behold I and the children which God hath given me.

Forasmuch then as the children are partakers of flesh and blood, he also himself likewise took part of the same; that through death he might destroy him that had the power of death, that is, the devil;

And deliver them who through fear of death were all their lifetime subject to bondage.

For verily he took not on [him the nature of: italics not in original Greek) angels; but he took on [him] the seed of Abraham.

Wherefore in all things it behoved him to be made like unto his brethren, that he might be a merciful and faithful high priest in things pertaining to God, to make reconciliation for the sins of the people.

For in that he himself hath suffered being tempted, he is able to succour them that are tempted."

The author doesn’t mention Yeshua until Hebrews 2:9, and he clearly expresses that the previous verses are about a different subject. Notice right before he says "but we see Jesus", the author says "but now we see not yet all things put under him [mankind]". This is because the first two chapters are about mankind- all of mankind. Yeshua is a man, and God put all things in subjection to him because this was God's purpose from the beginning.

"Verily, verily, I say unto you, The hour is coming, and now is, when the dead shall hear the voice of the son of God: and they that hear shall live.

For as the Father hath life in himself; so hath he given to the son to have life in himself;

And hath given him authority to execute judgment also, because he is the son of man." John 5:25

Letters of Saul

I'm pretty sure Saul believed that Yeshua preexisted as a divine entity, along the lines of Arianism. We could argue for thousands of years about what Saul was talking about, but there really is no need. He might have written 13 letters, but he is only one man. My answer to Why are the three accounts of Paul's conversion on the road to Damascus different? should explain why I feel no need to quote him.

Conclusion

Yeshua is a man because the Greek Scriptures say he is a man. When Yeshua exalts himself, he is actually exalting God and God’s word, because he says:

Jesus cried and said, He that believeth on me, believeth not on me, but on him that sent me.

And he that seeth me seeth him that sent me. [because he is the image of God]

I am come a light into the world, that whosoever believeth on me should not abide in darkness.

And if any man hear my words, and believe not, I judge him not: for I came not to judge the world, but to save the world.

He that rejecteth me, and receiveth not my words, hath one that judgeth him: the word that I have spoken, the same shall judge him in the last day.

For I have not spoken of myself; but the Father which sent me, he gave me a commandment, what I should say, and what I should speak.

And I know that his commandment is life everlasting: whatsoever I speak therefore, even as the Father said unto me, so I speak.

There are a plethora of verses that clearly distinguish Jesus from God Almighty and which make clear that Jesus is subservient to God - far too many to post. Once you start reading the scriptures while explicitly looking for such scriptures, you will find them in abundance.

John 5:19 Jesus gave them this answer: “Very truly I tell you, the Son can do nothing by himself; he can do only what he sees his Father doing, because whatever the Father does the Son also does.

John 14:28 “You heard me say, ‘I am going away and I am coming back to you.’ If you loved me, you would be glad that I am going to the Father, for the Father is greater than I.

1 Corinthians 15:27-28 ... Now when it says that “everything” has been put under him, it is clear that this does not include God himself, who put everything under Christ. 28 When he has done this, then the Son himself will be made subject to him who put everything under him, so that God may be all in all.

Matthew 28:18 Then Jesus came to them and said, “All authority in heaven and on earth has been given to me.

Luke 22:69 But from now on, the Son of Man will be seated at the right hand of the mighty God.

1 Timothy 2:5 For there is one God and one mediator between God and mankind, the man Christ Jesus

In fact, at no point does Jesus ever address himself as God but always refers to himself as the Son of God. This fact alone should give you pause, for we know what a "son" is and what a "father" is - and never is the father of a son also that son. They maybe very similar - but they are always distinct persons, distinct beings, where the first came before the second. It is true that God is spirit, not flesh, so there is arguably some leeway for interpretation here - but the fact is that God and Jesus revealed themselves in terms that we know and use on a daily basis: Father and Son. They did not provide an alternative interpretation of these terms - but used them as you or I use the term. As such, we shouldn't be trying to mystify the terms to explain away what they obviously are intended to mean.

Trinitarians will try to explain or otherwise ignore away such verses and obvious contradictions with their position - but they don't do so from the scriptures. I can't tell you the number of times I've been told: "That verse supports the Trinity because the scriptures all teach the Trinity" - no matter how clearly it contradicts them, like 1 Cor 15:27-28 above.

Note, also, that I grew up a Trinitarian. I started studying this stuff in depth to explicitly defend the Trinity, but was ultimately forced to accept the fact that not only is the Trinity not taught by the scriptures (nor by the Early Church Fathers), but that none of my fellow Christians have spent any serious time studying a matter which they claim to be THE defining belief of a Christian. Nor, coming from that same belief system, was it easy for me to let go of - for initially, to give up on the Trinity was the same as giving up on Christianity.

Perhaps a topic for another thread - but this is one of my big complaints, now, of most sects of Christianity: they make out acceptance of their doctrines as being the basis for salvation. With things like the Trinity they don't even require you to understand it (for they don't understand it either and call it a mystery). The scriptures make no such demands of us, but instead insist that we are judged by our actions, how we persisted in living our life:

Romans 2:6-11 God “will repay each person according to what they have done.”[a] 7 To those who by persistence in doing good seek glory, honor and immortality, he will give eternal life. 8 But for those who are self-seeking and who reject the truth and follow evil, there will be wrath and anger. 9 There will be trouble and distress for every human being who does evil: first for the Jew, then for the Gentile; 10 but glory, honor and peace for everyone who does good: first for the Jew, then for the Gentile. 11 For God does not show favoritism.

The best defense the Trinity has is that there are a couple verses, like John 1:1, where Jesus is addressed as God. However, this is argument falls on its face when you realize that many people have been called God/gods who are not literally God himself. This includes various angels, like the one in the burning bush (Exodus 3), Moses (Exodus 7:1), and the Jewish People (John 10:33-36).

It is also interesting to note verses like the following where even as Jesus is addressed as God, it is made clear that he has a God over him:

Hebrews 1:8-9 But about the Son he says, “Your throne, O God, will last for ever and ever; a scepter of justice will be the scepter of your kingdom. 9 You have loved righteousness and hated wickedness; therefore God, your God, has set you above your companions by anointing you with the oil of joy.”[e]

Many scriptures are used to establish a Unitarian position, check the following:

Jesus was created

Colossians 1:15-16 (NIV)

The Son is the image of the invisible God, the firstborn over all creation. 16 For in him all things were created: things in heaven and on earth, visible and invisible, whether thrones or powers or rulers or authorities; all things have been created through him and for him.

Revelation 1:1, 3:14 (ESV)

The revelation of Jesus Christ, which God gave him to show to his servants the things that must soon take place. He made it known by sending his angel to his servant John...14"And to the angel of the church in Laodicea write: 'The words of the Amen, the faithful and true witness, the beginning of God’s creation.

Many Bible commentators agree, the Son is referred to as wisdom personified (Proverbs 8:22 ^{footnote: a}). According to RS, NE, and JB, the one there speaking is said to be “created.”

Jesus was/is inferior to God and Father

Matthew 20:23 (NIV)

Jesus said to them, “You will indeed drink from my cup, but to sit at my right or left is not for me to grant. These places belong to those for whom they have been prepared by my Father.

Revelation 1:1 (NIV)

The revelation from Jesus Christ, which God gave him to show his servants what must soon take place. He made it known by sending his angel to his servant John

John 14:28 (NIV)

“You heard me say, ‘I am going away and I am coming back to you.’ If you loved me, you would be glad that I am going to the Father, for the Father is greater than I.

1 Corinthians 8:6 (NIV)

yet for us there is but one God, the Father, from whom all things came and for whom we live; and there is but one Lord, Jesus Christ, through whom all things came and through whom we live.

1 Corinthians 3:23 (NIV)

and you are of Christ, and Christ is of God.

1 Corinthians 15:24,28 (NIV)

Then the end will come, when he hands over the kingdom to God the Father after he has destroyed all dominion, authority and power...When he has done this, then the Son himself will be made subject to him who put everything under him, so that God may be all in all.

1 Corinthians 11:3 (NIV)

But I want you to realize that the head of every man is Christ, and the head of the woman is man,[a] and the head of Christ is God.

John 6:38

For I have come down from heaven not to do my will but to do the will of him who sent me.

Mark 13:32

“But about that day or hour no one knows, not even the angels in heaven, nor the Son, but only the Father.

Philippians 2:9

Therefore God exalted him to the highest place and gave him the name that is above every name,

Jesus isn't Almighty God

John 20:17 (NIV)

Jesus said, “Do not hold on to me, for I have not yet ascended to the Father. Go instead to my brothers and tell them, ‘I am ascending to my Father and your Father, to my God and your God.’”

John 17:3

Now this is eternal life: that they know you, the only true God, and Jesus Christ, whom you have sent.

Matthew 4:10 (NIV)

Jesus said to him, “Away from me, Satan! For it is written: ‘Worship the Lord your God, and serve him only.’”

Holy Spirit is not a person

Luke 1:41 (NIV)

When Elizabeth heard Mary’s greeting, the baby leaped in her womb, and Elizabeth was filled with the Holy Spirit.

Matthew 3:11 (NIV)

“I baptize you with water for repentance. But after me comes one who is more powerful than I, whose sandals I am not worthy to carry. He will baptize you with the Holy Spirit and fire.

Acts 10:38 (NIV)

how God anointed Jesus of Nazareth with the Holy Spirit and power, and how he went around doing good and healing all who were under the power of the devil, because God was with him.