HIS DIVINITY
In the scriptures Jesus is called 'The Word':
John 1:14 says: And the Word became flesh and dwelt among us, and we beheld His glory, the Glory of the only begotten of the Father...

In the following passages Jesus is declared to be the one who created all things:
John 1:1-3 says: In the beginning was the word(Jesus), and the word was with God(the Father), and the Word was God. He was in the beginning with God. All things were made through Him, and without Him nothing was made that was made.
Hebrews 1:2 says: (the Father)has in these last days spoken to us by His Son, Whom He has appointed heir of all things, through whom also He made the worlds;

Colossians 1:15-19 says: He(Jesus) is the image of the invisible God, the firstborn over all creation. For by Him all things were created that are in heaven and that are on earth, visible and invisible whether thrones or dominions or principalities or powers. All things were created through Him and for Him. And He is before all things and in Him all things consist. And He is the head of the body, the church, who is the beginning, the firstborn form the dead, that in all things He may have the preeminence. For it pleased the Father that in Him all the fullness should dwell,
In this passage we see that Jesus, "the first born from the dead "is the first of those who will be resurrected never to die again. And by Jesus, who created all things, Even the very atomic structure of the elements are held together. and do not blow themselves apart. How?
Colossians 2:9 says: For in Him dwells the fullness of the Godhead bodily;

In John 5:17-18 we read : But Jesus answered them, "My Father has been working until now, and I have been working." Therefore the Jews sought all the more to kill Him, because He not only broke the Sabbath, but also said the God was His Father, making Himself equal with God.
Notice that John does not say "Jesus said 'I am equal with the Father'" nor does John say "that is what the Jews thought he said or meant". John the writer of the gospel, is saying when Jesus said God was his father, everyone including Jesus the Jews and John himself Knew that Jesus meant He is equal to God the Father.

Exodus 3:13-14 says: Then Moses said to God, "Indeed, when I come to the children of Israel and say to them, 'The God of your father's has sent me to you' and they shall say to me, 'What is his name?' what shall I say to them?" And God said to Moses, "I AM who I AM." And He said "Thus you shall say to the children of Israel, 'I AM has sent me to you.'"
By this we see that the God of Israel calls himself by the name "I AM." In old testament Hebrew, new testament Greek, and in English it is improper to say "I am" without an object. For example "I am hungry". So when Jesus uses the name "I AM" he is taking the divine name for Himself. Some translations like the King James Version and the New King James, add "He" to some of those verses, but when they do they usually italicize the word.

John 8:56-59 says: "Your father Abraham rejoiced to see My day, and he saw it and was glad." Then the Jews said to Him, "You are not yet fifty years old, and have You seen Abraham?" Jesus said to them, "Most assuredly, I say to you, before Abraham was, I AM." Then they took up stones to throw at Him; but Jesus hid Himself and went out of the temple, going through the midst of them, and so passed by.
The Jews knew exactly what Jesus meant and tried to kill Him for it.

The same thing happened in John 10:30-33 "I(Jesus) and my Father are one." Then the Jews took up stones again to stone Him. Jesus answered them, "Many good works I have shown you from my Father. For which of these good works do you stone me?" The Jews answered Him, saying, "For a good work we do not stone You, but for blasphemy, and because You, being a man, make Yourself God."
And in John 8:24 Jesus gives us the warning: "Therefore I said you will die in your sins; for if you do not believe that I AM (he), you will die in your sins."

In Matthew 4:9-10 we read: And he(Satan) said to Him, "All these things I will give You if You will fall down and worship me." Then Jesus said to him "Get behind Me, Satan! For it is written, "You shall worship the LORD your God, and him only you shall serve."
In this scripture Jesus says to Satan, who is a fallen angel, you worship only God.
And yet in Hebrews 1:6 we read: But when he again brings the firstborn (Jesus) into the world, He says: "Let all the angels of God worship Him." This appears to be a contradiction, unless of course; Jesus, the Son, is God.
It continues in Hebrews 1:8 saying: But to the Son He says: "Your throne, O God, is forever and ever; A scepter of righteousness is the scepter of Your kingdom. You have loved righteousness and hated lawlessness; Therefore God, your God, has anointed You with the oil of gladness more then Your companions." So God the Father calls the Son, God.

In John 20:26-29 it says: And after eight days His disciples were again inside, and Thomas with them. Jesus came, the doors being shut, and stood in the midst, and said, "Peace to you!" Then He said to Thomas, "Reach your finger here, and look at my hands; and reach your hand here, and put it into my side. Do not be unbelieving but believing." And Thomas answered and said to Him, "My Lord and my God." Jesus said to him, "Thomas, because you have seen Me, you have believed. Blessed are those who have not seen and yet have believed."
Jesus did not rebuke Thomas for saying He was God, but he accepted his worship.

In Philippians 2:5-6 it says: Let this mind be in you which was also in Christ Jesus, who being in the form of God, did not consider it robbery to be equal with God, but made Himself of no reputation taking on the form of a servant, and coming in the likeness of men.
It was not wrong for Jesus to consider Himself equal to the Father, since he truly was. But he humbly emptied himself the glory of his divinity to become a man and die on the cross for the forgiveness of sins.

HIS PREEXISTENCE
Has Jesus always been God? Jesus, the man, was born of the virgin Mary. But we saw in John 1, and Colossians 1, Jesus' divine self created all things. If He was created then he could not of created all things, namely Himself.
Abraham, lived almost 2000 years before Jesus was born of Mary. Notice also in John 8:56-59 above, Abraham rejoiced when Jesus appeared to him.
In Micah 5:2 it says: But you Bethlehem Ephrathah, though you are little among the thousands of Judah, yet out of you shall come forth to me The One to be ruler in Israel, Whose goings forth have been from old from everlasting.
This says that Jesus, who is about to be born, has always existed, or in other words is from eternity.
Also notice when Jesus gave the 70 power over Demons he said in Luke 10:17 " I beheld Satan as lightning fall from heaven." This was not some vision, he was relating what he saw, because he was there!

Who do the cults say Jesus is?
Jehovah witnesses; the Archangel Michael
Mormons; one god of many, brother of Lucifer
Theosophy; an Incarnated world soul
Bahai; one of 9 manifestations of Divinity
Spiritists; an advanced Medium
Unitarians; an extraordinary good man

Who do Christians say Jesus is?
God the son, second person of the Trinity.
In conclusion we can confidently state in the scripture Jesus is God manifested in the flesh.
See 1 Timothy 3:16.
All Biblical quotations taken from the NRSV.