John 11:16 NASB Therefore Thomas, who is called [fn]Didymus, said to his fellow disciples, “Let us also go, so that we may die with Him.”
Didymus means the twin, so Thomas is believed to physically resembled Jesus. Returning to a city where they want to kill Jesus when you look a lot like Jesus takes a special type of courage. Then I also just plain like his attitude 'OK, so if Jesus is going back to Jerusalem to get killed, then we might as well join him.' It was similar to Peter's bold claim, except without the bravado.
John 20:24-29 NASB
24 But Thomas, one of the twelve, called [fn]Didymus, was not with them when Jesus came. 25 So the other disciples were saying to him, “We have seen the Lord!” But he said to them, “Unless I see in His hands the imprint of the nails, and put my finger into the place of the nails, and put my hand into His side, I will not believe.”
26 [fn]After eight days His disciples were again inside, and Thomas with them. Jesus *came, the doors having been [fn]shut, and stood in their midst and said, “Peace be with you.” 27 Then He *said to Thomas, “Reach here with your finger, and see My hands; and reach here your hand and put it into My side; and do not be unbelieving, but believing.” 28 Thomas answered and said to Him, “My Lord and my God!” 29 Jesus *said to him, “Because you have seen Me, have you believed? Blessed are they who did not see, and yet believed.”
Everyone always remembers Thomas for doubting, for not believing the words of men about such an incredible event. Yet Jesus does not condemn his lack of faith, but simply provides Thomas with what he needs in order to believe. How few places in the bible are the Deity of Christ presented as unambiguously as Thomas proclaimation 'My Lord and my God' ... Which Jesus does not offer anything even remotely like a correction, but accept the title as His due.
Some of us doubt because we want to know the Truth with absolute certainty. It is too important to us to risk getting it wrong. Thomas teaches us by example that God meets us at the point of our need ... even if our need is to know Truth.