We believe Jesus was God because of the Paschal Mystery ‘Ìâ‰âÂÌâ‰Ûù Jesus Christ's life, death, and resurrection.
From the moment of the Annunciation, we see Christ proclaimed as God, when the angel Gabriel tells Mary to name her child Jesus (Luke 1:31). Jesus' very name reveals His identity, for in Hebrew 'Jesus' means 'God saves.' Gabriel continues to say that 'the child will be called holy, the Son of God' (Luke 1:35).
Jesus Himself claims to be God throughout the Gospels as well. Jesus asked the Jews, 'Do you say . . . ‘Ìâ‰âÂÌâèÏYou are blaspheming,' because I said, ‘Ìâ‰âÂÌâèÏI am the Son of God'?' (John 10:36). Calling yourself God when you are not is blasphemy, the worst kind of sin for the Jews. That's why the Jews wanted to put Him to death.
I bet you've heard the saying, 'Actions speak louder than words.'
Throughout the Gospels, Jesus performs many miracles, giving sight to the blind, healing lepers and even raising his good friend Lazarus from the dead. All of these miracles invite us to believe in Him and His divinity. These miracles show in a tangible way that 'He was filled with the power of God's healing love' (YOUCAT 91).
The greatest proof, though, that Jesus Christ is God is the Resurrection. Jesus conquered death by death — rose from the dead — and saved all of humanity! St. Paul tells us that our faith would be in vain if Jesus did not rise from the dead (1 Corinthians 15:14).
As C.S. Lewis says, if Jesus didn't rise from the dead, He would have been either a liar or a lunatic.