Why is it important for people who believe in Trinity that Jesus is God?

In John 15:9-13, Jesus says this:

9 “As the Father has loved me, so have I loved you. Now remain in my love. 10 If you keep my commands, you will remain in my love, just as I have kept my Father’s commands and remain in his love. 11 I have told you this so that my joy may be in you and that your joy may be complete. 12 My command is this: Love each other as I have loved you. 13 Greater love has no one than this: to lay down one’s life for one’s friends.

Jesus says that the highest form of love is to lay down your life for your friends. There are of course many soldiers throughout history who have died for country or to protect family. Likewise police, firemen, fathers and mothers protecting their children, etc. All these have acted to prolong the life of the ones they love, but none could ever rescue from ultimate death. The Bible proclaims that God is love, and not just love, absolute, infinite and perfect love. If the Creator is greater than his creations who are willing to sacrifice themselves for the ones they love, then the Creator must certainly sacrifice himself. In order for Jesus' death on the cross to be the supreme sacrifice demonstrating the highest degree of love, Jesus must be God. If he was not God, then it still remains for God to offer himself, and the work of Jesus does not represent a finished work.

John 19:30 says:

30 When he had received the drink, Jesus said, “It is finished.” With that, he bowed his head and gave up his spirit.

If in fact the work of salvation is not finished, Jesus died in vain and his final words before he rose were a lie on which no man or woman can base their faith.

I leave you with 1 John 13-16:

13 This is how we know that we live in him and he in us: He has given us of his Spirit. 14 And we have seen and testify that the Father has sent his Son to be the Savior of the world. 15 If anyone acknowledges that Jesus is the Son of God, God lives in them and they in God. 16 And so we know and rely on the love God has for us.

God is love. Whoever lives in love lives in God, and God in them.

God is love.

It is important for anyone that believes the account of Jesus. He said that He is the Son of God.

For when you see Me, you are seeing the One who sent Me. John 12 : 45

He also said that He is one with the Father (God).

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 such a long time? Anyone who has seen Me has seen the Father. How can you say, ‘Show us the Father’? Don’t you believe that I am in the Father, and that the Father is in Me? The words I say to you I do not speak on My own authority. Rather, it is the Father, living in Me, who is doing His work. John 14 : 8 - 10

Quotes from New International Version with capitalization alterations.

Because John chapter 1 implies as much:

1 In the beginning was the Word, and the Word was with God, and the Word was God. ... 14 And the Word became flesh and dwelt among us, and we have seen his glory, glory as of the only Son from the Father, full of grace and truth. ESV

From this is derived the whole concept of LOGOS:

the Word of God, or principle of divine reason and creative order, identified in the Gospel of John with the second person of the Trinity incarnate in Jesus Christ

Also, if Jesus is God then Jesus has existed since the beginning, which is the foundation for another area of belief: that the "Angel of God" or "Captain of the Lord's host" in the OT is actually Jesus. See: Genesis 16:7, Joshua 5:14, and there are many more. These passages are called Christophanies:

Of the 214 usages of the Hebrew term used for “angel” [in the OT], about one-third of them refer to what is labeled by theologians as a “Christophany,” a temporary appearance of Christ in the Old Testament. It is certain, however, that this special angel of the Lord is divine, for Hagar “...gave this name to the LORD, who spoke with her [as the Angel of the LORD]: ‘You are the God who sees me,’ as she observed, ‘I have now seen the One who sees me’” (Gen 16:13).

Source: http://www.gordonconwell.edu/resources/Jesus-in-the-Old-Testament.cfm

Another justification for these being appearances of Jesus is that while no one would have bowed down and worshipped an angel, in every one of these appearances, the people in these situations bowed down and worshipped this Angel in the same way they would have worshipped God. This speaks to the divinity of the Angel before them.

Yet another justification for these being appearances of Jesus is in Colossians 1:

15 [Jesus] is the visible image of the invisible God. He is supreme over all creation. CJB

By this we can infer that no one has seen God the Father, and in any instance where someone encountered God (especially in the OT), they were seeing Jesus.

Furthermore, in Judges 13,

17 Manoah said to the angel of the LORD, "What is your name, so that when your words come to pass, we may honor you?" 18 But the angel of the LORD said to him, "Why do you ask my name, seeing it is wonderful?" NASB

Just as we do not know the true name of God (we have the tetragrammaton but we don't know the full spelling or how it would be pronounced), we do not know the true name of this Angel of the Lord -- thus they are equally divine.

So, you can see how Jesus' divinity is the foundation for a lot of scriptural interpretation.

P.S.: from reading this you may get the impression that I am implying that Jesus and God the Father are two separate divine beings. I most certainly am not. John 1:1 clearly states the Word was God, thus they are one and the same.

Why is it important for people who believe in Trinity that Jesus is God?

First, because people who believed in the Trinity did not believe it through reading it into the texts of the Scriptures but rather, the Scriptures itself forcefully evinces the fact of an eternal Triad. Without the Trinity, there is no God revealing himself to mankind and this entails the importance of Jesus' deity.

Second, because if Jesus wasn't God as the Father is God, then, it means that the Trinity isn't true and this entails that God did not save mankind whereas God alone could save.We don't even have any options because if Jesus wasn't God but only human by nature, then, it means that Jesus is sinful like the rest of us for Jesus cannot be other than our nature and hence, Jesus couldn't save.

In order to solve this dilemma, we must accept the Biblical teaching of the Trinity because it is important that Jesus is God or else, God did not provide salvific grace.

Bad News:

Mankind is unable to save themselves because all are of Adam and bears the consequence of the original sin ( Romans 5:12-21).

Good News:

The only solution for mankind's problem is to obey all of God's law without fail or else, he would end up experiencing God's wrath ( Ephesians 2:3).

But the New Testament records that the Law was given for the purpose of knowing that no one is able to save themselves but rather, if there is such salvation available, it is only by God's grace which is the case in the NT ( Romans 3:20).

There are three options to be used for saving mankind:

1) God 2) Angels 3) Humans

Option no. 1 is a "yes" because God alone can give grace of forgiveness and new life for he was the recipient of the human transgression ( Ephesians 1:6).

Option no 2 is a "no" because Angels are neither giver of grace nor affected by mankinds' condition.

Option no. 3 is a "yes" because mankind needs to pay for its sin but the problem is that mankind is unable ( Matthew 19:25-26).

Conslusion:

Only God is able to save mankind from its terrible condition because neither angels nor mankind is able.But we have another problem, God is not man and only man can pay for his sins.In order for God to forgive mankind and be reconciled to him, humans must pay the price of his sins and not God for God wasn't the one who sinned.This problem is solved in the Incarnation of our Lord Jesus.

The Incarnation

God's plan of salvation is a wise plan indeed because he sent his own Son in the likeness of sinful flesh (Romans 8:3). It is wise because it works. God's salvific act is an act of perfection, coming from his substance ( 1 Corinthians 1:24, Hebrews 1:3).

The incarnation teaches the one gospel, that is, that the μονογενὴς Θεὸς took on human flesh and spirit in order to live human life under the law and to destroy the works of the devil by his death on the cross and resurrection( John 1:1,14,18, 1 Corinthians 15:3, 1 John 3:8).

Acts 20:28 said that God purchased the church with his own blood.

Even the sub-apostolic and pre-nicene fathers concur:

I have become acquainted with your name, much-beloved in God, which you have acquired by the habit of righteousness, according to the faith and love in Jesus Christ our Saviour. Being the followers of God, and stirring up yourselves by the blood of God, you have perfectly accomplished the work which was beseeming to you. (Epistle of Ignatius to the Ephesians, Chapter 1. Praise of the Ephesians Chapter 1).

So far as I know, "we are not our own, but bought with a price;" and what kind of price? The blood of God. (Tertullian, To His Wife Book 2 Chapter 3)

The doubt arises if Jesus is God and is one of the GodHead only when we fail to see Christ in the old testament. Lots of Christians think that Trinity is only in the new testament however Trinity is mentioned in the whole Holy Bible.

One God, three persons have been all there from the 1st chapter till the last chapter of the Holy Bible.

Few Old Testament verses to support them Gen. 1:26, Gen. 3:22, Psalm 45:6-7, Isaiah 6:8.

Another old testament verse that supports Trinity is Isa. 48:16-17 "Come near to Me, hear this: I have not spoken in secret from the beginning; from the time that it was, I was there. And now the Lord GOD and His Spirit have sent Me."Thus says the LORD, your Redeemer, the Holy One of Israel: "I am the LORD your God, who teaches you to profit, who leads you by the way you should go.

Lets examine this again because this theme occurs over and over Isaiah 48:16:“From the beginning from the time that it was, I was there: (1st person) and now the Lord GOD (2nd person) and His Spirit, (3rd person) hath sent me (1st person).”

The Trinity Is Foreshadowed In Benedictions

The Trinity is also foreshadowed in the triple benediction of Numbers 6:24-27. The LORD bless you and keep you; the LORD make his face shine upon you and be gracious to you; the LORD turn his face toward you and give you peace. So they will put my name on the Israelites, and I will bless them.

The doxology of Isaiah 6:3 also gives hint of the Trinity. And they were calling to one another: Holy, holy, holy is the LORD Almighty; the whole earth is full of his glory (Isaiah 6:3).

Few New Testament verses to support them Matt. 3:16-17, 1 Cor. 12:4-6, 2 Cor. 13:14, Eph. 4:4-6, 1 Pet. 1:2, Jude 20-21

So it's not to believe if Jesus is God or not, but to accept Jesus as God.

It’s important for Jesus to be both fully God and fully man because without being both he could not have mediated between God and man and could not have made an acceptable sacrifice for sin.

Perhaps the clearest scriptural evidence for this is Job 9:32-33

For he [God] is not a man, as I am, that I might answer him, that we should come to trial together. There is no arbiter between us, who might lay his hand on us both.

Since God is of an entirely different nature than man, we can’t simply have another man mediate for us. We can’t even have another God mediate (if there were one). We need nothing short of a God-man to arbitrate or else he can't “lay his hand on us both”.

Psalm 49:7-9 gives further evidence that the sacrifice of a mere man will not suffice in atoning for sin:

Truly no man can ransom another, or give to God the price of his life, for the ransom of their life is costly and can never suffice, that he should live on forever and never see the pit.

These additional passages may shed more light for you. They each show various aspects of why Jesus must have been both God and man or he could not have done what he did for us: 1 Samuel 2:25; Job 16:19-21; Hebrews 2:14–18; 7:26; 9:22.

Jesus' divinity is not strictly a protestant assertion: The Blessed Trinity (Roman Catholic).

Jesus' divinity is crucial to his message. He made such assertions, and if we are to trust anything he says, then everything he says must be true. Similarly, if we are to trust anything the Biblical authors said, we must trust all of it.

The testimony of scripture is that Jesus is God. Here are some more thorough treatments of this idea: Bible Verses Stating Jesus was God, Jesus is God, Jesus-God

The essential message of salvation is that God himself became human and paid the price for our sins. Had God just chosen some good person to die, it would not have been the same kind of personal sacrifice on God’s part. Not only that, but only a perfect sacrifice would do it, and nobody but God himself could have been perfect (Ro 3:23, 1 John 1:8).

The main reason that it is important to Protestants, that Jesus is the son of God, is because that is the basic precept on which their salvation depends. If Jesus were not deity, (or God) he could not keep the promises he made concerning salvation.

All Scripture is quoted from the King James translation.

example:

John 10:15 through 18 As the Father knoweth me, even so know I the Father: and I lay down my life for the sheep. And other sheep I have, which are not of this fold: them also I must bring, and they shall hear my voice; and there shall be one fold, and one shepherd. Therefore doth my Father love me, because I lay down my life, that I might take it again. No man taketh it from me, but I lay it down of myself. I have power to lay it down, and I have power to take it again. This commandment have I received of my Father.

In the above passage what you will find, is that Jesus has promised that he will give salvation to his sheep. Jesus used the example of a shepherd because the people were familiar with sheep herding, and he also referred to those being saved as his sheep.

But the really important part is the part about his laying down his life and being able to take it up again.

If Jesus did not have the power to take up his own life again, how would he ever have the ability to give eternal life to anyone else?

John 10:28 And I give unto them eternal life; and they shall never perish, neither shall any man pluck them out of my hand.

John 6:54 Whoso eateth my flesh, and drinketh my blood, hath eternal life; and I will raise him up at the last day.

Unless Jesus were God and not just a good man all of these would be hollow promises, since salvation is of God:

Luke 3:6 And all flesh shall see the salvation of God.

The veracity of Jesus claim is found in the Old Testament. Particularly in the Book of Isaiah, which is most descriptive, and also in many other Prophets from many years before his birth, which is foretold in Isaiah chapter 7:

John 5:39 Search the scriptures; for in them ye think ye have eternal life: and they are they which testify of me.

Isaiah 7:13 and 14 And he said, Hear ye now, O house of David; Is it a small thing for you to weary men, but will ye weary my God also? Therefore the Lord himself shall give you a sign; Behold, a virgin shall conceive, and bear a son, and shall call his name Immanuel.

Finally; if Jesus were not God all who have put their trust in Jesus for their Salvation would still be lost with no hope of eternal life.

John 6:37 All that the Father giveth me shall come to me; and him that cometh to me I will in no wise cast out.

Mark 2:17 When Jesus heard [it], he saith unto them, They that are whole have no need of the physician, but they that are sick: I came not to call the righteous, but sinners to repentance.

Luke 19:10 For the Son of man is come to seek and to save that which was lost.