And after eight days His disciples were again inside, and Thomas with them. Jesus came, the doors being shut, and stood in the midst, and said, “Peace to you!” Then He said to Thomas, “Reach your finger here, and look at My hands; and reach your hand here, and put it into My side. Do not be unbelieving, but believing.” And Thomas answered and said to Him, “My Lord and my God!” Jesus said to him, “Thomas, because you have seen Me, you have believed. Blessed are those who have not seen and yet have believed.” (vv.26-29)
After eight days: The idea here is that Jesus had an additional meeting with the disciples (now including Thomas) eight days after the first one. And again Jesus enters the room in the same mysterious and remarkable way in which He had before in verse 19 (the doors being shut, and stood in the midst). Jesus also gave the same greeting (Peace to you!).
At this meeting Jesus grants Thomas the evidence he demanded in verse 25, "Reach your finger here, and look at My hands; and reach your hand here, and put it into My side." Jesus was not obligated to do this; He could have rightly demanded faith from Thomas on the basis of the reliable evidence from others. Yet in His mercy and kindness, Jesus gave Thomas what he asked for.
Jesus then gives Thomas a command, "Do not be unbelieving, but believing." Jesus was generous and merciful to Thomas and his unbelief, but He did not praise his unbelief. Jesus wanted to move him from doubt and unbelief to faith. Because Thomas did not believe in the resurrected Jesus, Jesus considered him unbelieving. Thomas’ response was an immediate transition from declared unbelief (John 20:25) to radical belief (John 20:28). He addressed Jesus with titles of deity, calling Him Lord and God. It is also significant that Jesus accepted these titles, and did not tell Thomas, “Don’t call Me that.”
Peter would later says to those who believed, “Whom having not seen you love. Though now you do not see Him, yet believing, you rejoice with joy inexpressible and full of glory, receiving the end of your faith—the salvation of your souls” (1 Peter 1:8-9).
The lesson here for us is, true faith comes from the reliance upon the Word of God, and not on the eyes of man. For trusting in what one sees is not trust at all, it requires no faith. But relying on God's Word, even when we can not see the outcome, is evidence of a much "stronger faith."
The Truth: But Simon answered and said to Him, “Master, we have toiled all night and caught nothing; nevertheless at Your word I will let down the net.” (Luke 5:5)