20:26 John located this post-resurrection appearance eight days after Easter Sunday, namely the following Sunday. His "eight days"(Gr. hemeras okto) evidently included both Sundays. Perhaps he identified the day because, by the time John wrote, Sunday had become the day of worship for Christians, when they commemorated Jesus' resurrection. They worshipped Him on Easter Sunday, then again the following Sunday, and then on succeeding Sundays from then on (cf. Acts 20:7). Sunday worship has its roots in tradition rather than commandment.
The disciples were still meeting behind closed doors because they feared the Jewish authorities (cf. v. 19). Jesus again materialized in the presence of these disciples as He had a week earlier (v. 19). He also repeated His benediction (v. 21). Perhaps Jesus did these things because the disciples had told Thomas that He had appeared this way and had said these things. This would have bolstered Thomas' faith.
20:27 Jesus then invited Thomas to satisfy himself that He really was the crucified Jesus, as Thomas had said he would have to do to believe that Jesus was alive. Jesus knew what Thomas had said even though He had not been physically present when he had said it. This is further proof of Jesus' deity. The purpose of this test was not just to satisfy Thomas' curiosity, however. It was to bring him to faith that Jesus was the resurrected Messiah. We could render Jesus' statement literally, "Do not be unbelieving but believing."
20:28 Evidently Thomas did not take up Jesus' offer. The sight of his Savior seems to have been enough to convince him (cf. v. 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. 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 hislord in a fuller sense than before, and he now believed that Jesus was fully God.
"The repeated pronoun mydoes not diminish the universality of Jesus' lordship and deity, but it ensures that Thomas' words are a personalconfession 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."655
Now Thomas believed as his fellow disciples had come to believe (cf. v. 25). His confession is a model that John presented for all future disciples. It is the high point of this Gospel (cf. 1:1, 14, 18). John's other witnesses to Jesus' deity were John the Baptist (1:34), Nathanael (1:49), Jesus Himself (5:25; 10:36), Peter (6:69), the healed blind man (9:35), Martha (11:27), and John the Apostle (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."656
20:29 We could translate Jesus' first sentence as either a question or a statement. It confirmed the reality of Thomas' belief in either case, and it prepared for the beatitude that followed (cf. 13:17). "Blessed"(Gr. makarios) does more than just describe the person in view as happy. It also declares him or her acceptable to God (cf. Matt. 5:3-12).
Most believers have believed on Jesus because of sufficient evidence without the physical confirmation that Thomas required (cf. v. 8; 1 Pet. 1:8-9). Those were the people whom Jesus had in view when He made this statement. This beatitude does not make believers who live after Jesus' ascension superior to those who saw Him in the flesh. Rather it guarantees their blessing by God.
"Thomas's declaration is the last assertion of personal faith recorded in this Gospel. It marks the climax of the book because it presents Christ as the risen Lord, victorious over sin, sorrow, doubt, and death. It also presents the faith that accepts not only the truth of what Jesus said but also the actuality of what he was--the Son of God. In the experience of Thomas, the writer has shown how belief comes to maturity and how it changes the entire direction of an individual life."657
"The growth of belief depicted in the Gospel of John thus moves from an initial acceptance on the testimony of another to a personal knowledge marked by loyalty, service, and worship; from assumption of the historicity and integrity of Jesus to a personal trust in Him; from an outward profession to an inward reality; from attending to His teachings to acknowledging His lordship over life. Full belief may not be attained instantly; yet the incipient and tentative belief is not to be despised."658
(NT only) to listen to the NET Bible 
