In the Gospel of John, Thomas doubted Jesus’ resurrection until seeing his wounds.
John says Thomas was absent when the risen Jesus first appeared to the other disciples. When they told him what they had seen, Thomas said he would not believe unless he saw the marks of the nails and placed his hand in Jesus’ side.
A week later, Jesus appeared again and invited Thomas to examine the wounds. Thomas responded by calling Jesus “My Lord and my God,” one of the strongest declarations about Jesus’ identity in the Gospel of John.
Thomas is also called Didymus, a Greek term meaning “Twin.” The passage is the source of the familiar expression “Doubting Thomas,” although the Gospel itself ends the episode by praising those who believe without seeing.