This is a condensed version of a discussion found in the 'Trinity Index' of the old MSN Group.
John 20:28, "Thomas answered, 'My Lord and my God"
"Thomas had said (verse :25) that unless something happened he would "not believe." What was it that Thomas refused to believe? Was it that he refused to believe that Jesus was equally God with the Father? There is certainly no hint of this before or after Thomas' statement at John 20:28.
If the disciples had learned, upon seeing the resurrected Jesus, that he was God, certainly they would have indicated this! But notice, neither before nor after receiving Holy Spirit (:22) did they kneel or do any act of worship such as one would certainly do upon becoming aware of being in the presence of God!
Notice that the disciples who had seen Jesus earlier did not tell Thomas that Jesus was God (:25)! This is an incredible oversight if they had really believed they had seen God! Certainly, if they had discovered that Jesus was really God when they saw him resurrected, they would have talked of nothing else!
If, on the other hand, they had already known that Jesus was God even before seeing his resurrected form, then Thomas, too, would have already known about it and certainly could not have meant: "Unless I see ... the print of nails [etc.] ... I will not believe [Jesus is God]."
No, the context of John 20:24, 25, and 29 shows that Thomas refused to believe that Jesus had been resurrected from the dead. (See footnote for John 20:8 in The NIV Study Bible, Zondervan, 1985: "John did not say what [the disciple who saw the empty tomb of Jesus] believed, but it must have been that Jesus was resurrected." - Also see Barclay's The Daily Study Bible Series: The Gospel of John, Revised Edition, Vol. 2, p. 267, and pp. 275, 276.)"