In discussing the Resurrection of Christ, we need to keep in mind that this was completely unexpected on the disciples’ part. They saw him being led away by soldiers, one of them (John) actually watched him die, and they figured they were next.
So even though John believed in the Resurrection and the women testified to it, most of the remaining disciples were hiding in fear from the Romans. The last thing they were expecting was a visit from Jesus.
I’m really trying to definitively say nothing more and nothing less than what Scripture tells us. They were together in a locked room, and the Gospel says that "Jesus came and stood among them." This seems to indicate that he. . . what? Teleported in, to use a sci-fi term? Looks like it to me, but since John doesn’t give us any more details than that, I don’t want to go further into speculation.
Here’s the best explanation I’ve heard about this. When Adam and Eve were created, they had complete dominion over the physical creation on earth. That’d presumably include their physical bodies. Once they rebelled against their Maker, this control over creation was mostly removed. We still control it to some degree; we have dominion over the animals, but this control is—with a few notable exceptions like dogs--rule by fear and force.
I also believe this changed with Jesus’ resurrection. Paul said that "[We] know that since Christ was raised from the dead, he cannot die again; death no longer has mastery over him." He’s not subject to decay, or sickness, or infirmity, or tiredness. We know that he was subject to at least tiredness and thirst and hunger while on earth. Not any longer. For a more complete discussion on this, see here.
I remember this really touching story I once heard. A little girl came up to her pastor and said “Pastor, do you know what will be the only thing up in Heaven that's been made by men?” The pastor told her “My dear, there won’t be anything made by men up in Heaven.” She insisted “Yes, there will be.” He tried to correct her, and finally asked her “So what are you talking about?” She said, “There will only be one work done by men up there: the scars on Jesus’ body.”
I love what I call “throw away” lines: where an author just inserts a phrase or line that’s just casually mentions something I’d really like to examine further, and then just goes on without explaining it. Like when Paul says “Do you not know that we will judge angels?" Um, no Paul, we didn’t. We have something like that here: In order to prove that he is who they think he is, he shows them his “hands and side.” Apparently the wounds he had sustained in his hands (really his wrists, but they considered that part of the hand) and his side still bore the scars of his ordeal. For some reason, the Father has chosen never to erase them. Why? We’ll never know.
His words “Peace be with you!” have real authority when spoken by the risen Christ, don’t they? I can say “I hope you have peace in your life,” or “I really wish for world peace.” But the Risen One, the One who conquered Satan and Death, has the ultimate authority in this universe. And when he declares “peace” to our troubled hearts, he can actually do it.
Keep in mind the importance of context in regards to vs. 22. He breathed on them and gave a taste of the Holy Spirit, but the full, permanent, complete gift of the Holy Spirit and the birth of the Church would occur at Pentecost. But that is what Pentecost was: The breath of Jesus, breathing life into his followers.
OK, we have to tackle a slightly thorny subject, namely the last verse of today’s reading. Does this mean that if we don’t forgive peoples’ sins, God won’t forgive them either? If we look at the NASB’s rendition of this passage, it actually makes more sense. It’s completely compatible with the Greek—and makes a lot more sense theologically—to interpret it as “If you declare that someone is forgiven their sins, their sins will have already been forgiven.” We don’t forgive or not forgive anyone and thus control someone else's standing with the Lord. He promises that if anyone receives Christ, their sins are forgiven. Based on this, we can proclaim to the believer that their sins are already forgiven. He takes the initiative, and we follow his directions and tell forgiven people that they are, in fact, forgiven. Make sense?
But don’t miss the wonderful part of this. What an awe-inspiring privilege to be able to tell people that they’re forgiven, that their sins will never be brought up again. That’s something we should never forget.
And for your edification, here's "Known By The Scars" by Michael Card
Lord Jesus, what an awesome privilege to be able to tell people that they’re forgiven. Thank you.