John 20.19-20 cont.
19 During the evening of that first day of the week (of Sabbaths), the doors having been shut, because the disciples were afraid of the Jews, Jesus came and stood amongst them and said (says) to them: “Peace to you”.
20 And saying this His showed both His hands and side, and the disciples rejoiced at seeing the Lord.
John tells us that the doors were locked, and the inference is that they remained locked. In Luke 24.36 we read:
36 Now as they were saying these things He (Jesus) stood in the middle of them, and said to them “Peace be with you”.
This would seem to be the same occasion.
Jesus had already appeared to the two on the road to Emmaus. They were blessed to experience seeing the resurrected Lord Jesus for a second time, since He had appeared to them a few hours earlier.
In both John and Luke’s gospel the inference is that Jesus miraculously entered the room without going through the locked door or the solid walls. Such was the nature of His resurrected body. The same inference is to be taken from Matthew’s gospel, where we read:
 Then the eleven disciples left for Galilee, going to the mountain where Jesus had told them to go.
 When they saw Him, they worshiped Him—but some of them still doubted! – Matthew 28.16-17 (NLT).
In Acts chapter 1 Luke tells us:
 During the forty days after His crucifixion, He (Jesus) appeared to the apostles from time to time and proved to them in many ways that He was actually alive – Acts 1.3 (NLT).
It appears from what Luke writes that Jesus visits the disciples in a miraculous way, a way that is not common to humanity. We are led to believe that there was something different about the body of Jesus, since He seems to be able to pass through solid objects, and to suddenly appear before them.
However, during His ministry we know that Jesus was able to walk on water, which physically speaking, is not possible. On that occasion Jesus invited Peter to step on to the water and walk to Him. He did this, and he took some steps towards Jesus, before beginning to sink. On that occasion Jesus said that the cause of Peter’s sinking was his doubt, and lack of faith.
Jesus was always full of faith.
In the resurrection appearances of Jesus it is plain to see that the disciples initially thought that Jesus was a spirit, ghost, which is why He showed them His hands and side.
A number of years ago someone once said to me: “Be prepared for Jesus to interrupt you”. Advice I pass on.