Thomas said to him, “My Lord and my God!”
Then Jesus told him, “Because you have seen me, you have believed; blessed are those who have not seen and yet have believed.”
Jesus performed many other signs in the presence of his disciples, which are not recorded in this book. But these are written that you may believe that Jesus is the Messiah, the Son of God, and that by believing you may have life in his name.
John 20:28-31 (NIV)