Jesus is God (see verses below) according to the New Testament of the Bible, so therefore Jesus is the same God in the Old Testament, as well.
A massive 17+ verses in the Bible show that they believe Jesus is god.
The first words of John's gospel imply that Jesus ("the Word") is God.
In the beginning was the Word, and the Word was with God, and the Word was God. John 1:1
And the Word was made flesh, and dwelt among us. John 1:14
And Jesus (sometimes) claimed to be God.
- By forgiving sins. (Only God can forgive sins.)
Jesus ... said unto the sick of the palsy; Son, be of good cheer; thy sins be forgiven thee. And, behold, certain of the scribes said within themselves, This man blasphemeth ... That ye may know that the Son of man hath power on earth to forgive sins, (then saith he to the sick of the palsy,) Arise, take up thy bed, and go unto thine house. Matthew 9:2-6, Mark 2:3-12
Therefore did the Jews persecute Jesus, and sought to slay him, because he had done these things on the sabbath day. But Jesus answered them, My Father worketh hitherto, and I work. Therefore the Jews sought the more to kill him, because he not only had broken the sabbath, but said also that God was his Father, making himself equal with God. John 5:16-18
- By declaring himself, "Lord of the Sabbath."
- By claiming to be the same as God.
He that hath seen me hath seen the Father. John 14:9
- By saying that he existed before Abraham, using one of God's names, "I am."
Jesus said unto them, Verily, verily, I say unto you, Before Abraham was, I am. John 8:58
After hearing Jesus say these things, the Jews tried to stone him to death for claiming to be God.
I and my Father are one. Then the Jews took up stones again to stone him. John 10:30-31
The Father is in me, and I in him. Therefore they sought again to take him. John 10:38-39
And when Thomas called Jesus God, Jesus didn't correct him. Rather, he said that everyone should believe he is God, even those who have never seen him.
And Thomas answered and said unto him, My LORD and my God. Jesus saith unto him, Thomas, because thou hast seen me, thou hast believed: blessed are they that have not seen, and yet have believed. John 20:28-29
The New Testament (sometimes) also refers to Jesus as God.
- That the church of God was purchased with the blood of God (or maybe the Holy Ghost).
Take heed therefore unto yourselves, and to all the flock, over the which the Holy Ghost hath made you overseers, to feed the church of God, which he hath purchased with his own blood. Acts 20:28
- That Jesus created all things.
For by him [Jesus] were all things created. Colossians 1:16
- That the fulness of the Godhead dwells in Jesus bodily.
For in him [Jesus] dwelleth all the fulness of the Godhead bodily. Colossians 2:9
- That God was made manifest in Jesus's flesh.
God was made manifest in the flesh. 1 Timothy 3:16
- That Jesus is the great God who is in the form of God, is equal to God, and sits on the throne of God.
Looking for that blessed hope, and the glorious appearing of the great God and our Saviour Jesus Christ. Titus 2:13
Who, being in the form of God, thought it not robbery to be equal with God. Philippians 2:6
But unto the Son he saith, Thy throne, O God, is for ever and ever: a sceptre of righteousness is the sceptre of thy kingdom. Hebrews 1:8
In the book of Revelation, Jesus calls himself the first and the last, and the alpha and the omega. (Which arguably means that he thinks he's God.)
I am the first and the last. Revelation 1:17
I am Alpha and Omega, the beginning and the end, the first and the last. Revelation 22:13