John 20:28

Evidently Thomas did not take up Jesus’ offer. The sight of his Savior seems to have been enough to convince him (cf. John 20:29). Thomas then uttered one of the most profound declarations of saving faith in Scripture. For a Jew to call another human being "my Lord and my God" was blasphemy under normal circumstances (cf. John 10:33). Yet that is precisely who Thomas believed Jesus was. It is also who John presented Jesus as being throughout this Gospel. Both titles were titles of deity in the Old Testament. Thomas had come to believe that Jesus was his lord in a fuller sense than before, and he now believed that Jesus was fully God.

"The repeated pronoun my does not diminish the universality of Jesus’ lordship and deity, but it ensures that Thomas’ words are a personal confession of faith. Thomas thereby not only displays his faith in the resurrection of Jesus Christ, but points to its deepest meaning; it is nothing less than the revelation of who Jesus Christ is. The most unyielding sceptic [sic] has bequeathed to us the most profound confession." [Note: Carson, The Gospel . . ., p. 659.]

Now Thomas believed as his fellow disciples had come to believe (cf. John 20:25). His confession is a model that John presented for all future disciples. It is the high point of this Gospel (cf. John 1:1; John 1:14; John 1:18). John’s other witnesses to Jesus’ deity were John the Baptist (John 1:34), Nathanael (John 1:49), Jesus Himself (John 5:25; John 10:36), Peter (John 6:69), the healed blind man (John 9:35), Martha (John 11:27), and John the Apostle (John 20:30-31).

"Nobody has previously addressed Jesus like this. It marks a leap of faith. In the moment that he came to see that Jesus was indeed risen from the dead Thomas came to see something of what that implied. Mere men do not rise from the dead in this fashion. The One who was now so obviously alive, although he had died, could be addressed in the language of adoring worship." [Note: Morris, p. 753.]