John 20:19 On the evening of that first day of the week, when the disciples were together, with the doors locked, Jesus came and stood among them and said, “Peace be with you!”

 Jesus has been crucified and the disciples are in total disbelief. They are afraid the Jewish leaders are also going to come and arrest them, so they are hiding in a house securely locking all the doors. Then Jesus appears before them and shows them HIS wounds on HIS hands and side.  Lesson: Jesus is alive and even when all the earthly doors are locked, HE will meet with us.  Now one disciple, Thomas, is not among them when they see the resurrected Jesus. So, when they see him, they enthusiastically tell Thomas that they have seen Jesus. Thomas doesn’t believe them. This is where we get the phrase doubting Thomas. He says that unless he puts his fingers in the hole of Jesus’ hands and puts his hand in the spear wound on HIS side he would never believe.