The Scriptures are filled with prophetic messianic messages about Jesus. The Lord even expressed Himself to be the Messiah to the hardened Pharisees in John 5:39 saying, “You search the Scriptures because you think that in them you have eternal life; it is these that testify about Me.” It not only testifies about Him being the Messiah, but also being the second personality in the Godhead. In the book of Isaiah God proclaimed, “I am the LORD, that is My name; I will not give my glory to another, nor My praise to graven images” (42:8). Jehovah was very serious when He made such a proclamation: not one created being or materialistic idol will be glorified and praised as gods or as God Himself.
When John fell down to worship an angel of God he said to the apostle, “Do not do that. I am a fellow servant of yours… Worship God” (Revelation 22:9). When the people worshiped king Herod who sat upon his judgement seat “an angel of the Lord struck him because he did not give God the glory, and he was eaten by worms and died” (Acts 12:21-23). When the centurion Cornelius met the apostle Peter, he fell down at his feet to worship him, but the apostle warned him saying, “Stand up; I too am just a man” (Acts 10:26). Throughout the inspired word we see men either struck down by God who tried to get His glory or men (and angels) urging the people not to worship them but God alone.
However, looking at the life of Christ throughout the gospels, we receive an opposite reaction from Christ. He did not forbid but allowed worship and praise from people (Matthew 21:9; Matthew 28:9, 17). Surely if Christ was a created being like the angels and the rest of us the Father would have struck Him dead or exposed Him. Therefore, Christ is not a created being (As Jehovah Witnesses and nonbelievers of the Trinity claim Him to be), but eternal. He has always existed with the Father and the Holy Spirit (John 1:1). When the Lord was praying in the garden of Gethsemane before He was to be handed over and crucified, He uttered these words: “Now, Father, glorify Me together with Yourself, with the glory I had with You before the world was” (John 17:5). This verse beautifully compliments and does not contradict Isaiah 42:8 when God said He will not give His glory or praise to another. The Father was not giving it to Christ; rather, He was returning the glory back to Jesus when He decided to lay some of the privileges as God aside when He manifested in the flesh to become our ultimate sacrifice (Philippians 2:5-8).
Thomas also knew the Lord Jesus Christ to be Deity when He rose again from the dead with power–so much so that he called Him “My Lord and My God!” (John 20:28).