When the rumor of the Lord's body disappearing from the cave spread, Thomas alone did not believe in the miracle and asked for proof - to touch Jesus' wounds from being nailed to the cross. Then the risen Christ appeared to his disciples and addressed the unbelieving Thomas, saying, "Give your finger here and see my hands; give your hand and put it in my side, and do not be an unbeliever, but a believer." 

The apostle Thomas is known not only for the gospel story of his unbelief, but also as one of Christ's most sacrificial disciples.