St. Matthew alone tells us that the stone was still blocking the entrance of the tomb when Christ came forth. He says: “After the Sabbath, as the first day of the week was dawning, Mary Magdalene and the other Mary came to see the tomb. And behold, there was a great earthquake; for an angel of the Lord descended from heaven, approached, rolled back the stone, and sat upon it.” The angel does not roll back the stone in order that Christ may come forth, but in order to show the women the Christ had already risen and come forth from the tomb.
You may notice that, in most artistic depictions of the Resurrection, the tomb is already open when Christ rises. But this is not really quite accurate: he came forth from the tomb when it was still completely closed!
Why is it important to note that the stone was rolled back after Christ had already risen and come forth? St. Matthew tells us this detail, so that there can be no doubt about whether Christ’s body was stolen during the night. If the stone was sealed and the women saw it opened, they would be able to testify that the body could not have been taken during the night, but that Christ had miraculously risen and come forth from the tomb, when it was still sealed shut!
But how did Jesus exit the tomb, when the stone was blocking the opening?
St. John tells us that Jesus was able to walk through walls, when he entered the closed room where the disciples were hiding. Though all the doors were locked, Jesus came into their midst, obviously passing through the walls. (Jn 20:19)
This is also what happened when Jesus came forth from the tomb. Though the stone sealed the entrance, Christ passed through the stone walls of the tomb. When the women came and the stone was rolled back, they saw that their Lord was not in the tomb, but had risen from the dead.
But this raises another question: How did Christ walk through walls? Was this proper to his glorified body? Interestingly, St. Thomas says that this ability to walk through walls was not proper to Christ’s body through its glorification, but was the effect of Christ’s divine power. (ST III, q.54, a.1, ad 1)
This means that, ordinarily, even after the resurrection, Christ could not walk through walls. Still, on certain occasions (like when he exited the tomb and when he entered the locked room where the apostles were), through his divine power working in his glorified body, Christ walked through walls. (ST supplementum, q.83, a.2)
This means that the bodies of the saints, after the resurrection, will not ordinarily walk through walls. Indeed, since the glorified bodies of the saints will still be real, physical bodies, all the necessary properties of physical bodies will remain (and bodies cannot pass through other matter). In addition to these natural properties, certain other graces will be bestowed: immortality, brightness, agility, subtlety, etc. These new properties given to the glorified bodies of the saints will allow them to walk on water, to shine brightly, to appear under various forms, to move about with great speed, etc—but this will not include the ability to walk through walls.