As God breathed life into the creature of clay in the garden, so the Risen Christ breathes life into the lifeless body of fearful disciples. Finally, both to Thomas, and to others, Jesus shows his scars as a sign. Signs are meant to be read and understood and followed. People have scars, and with them, a story. A story of a fall, of a battle or an accident or an assault.
Most scars are on the inside, scars from cruel words, and from painful episodes in our lives.
Some wounds are self-inflicted, and we keep those scars hidden, but they reveal wounds that have not healed. Jesus' scars were a means of identifying him. Because the scars were there, the disciples knew it was Jesus in their midst. His scars told a story they knew too well, one of betrayal and abandonment at their hands. The Risen Lord kept his scars.