One of the things I love about the Low Sunday Gospel is the manner of Christ's appearance to His disciples. I find the setting of this appearance, the time and place, to be most significant.
Where does He appear to His primitive Church? Does He appear in the midst of their bold action of preaching and evangelization out in the world, as manifestation of and reward for their witness of the Gospel? No. He appears in a locked room (fores essent clausae), where they were gathered (congregati), for fear of the Jews. This reminds me of a couple things. One is that we too hide, all too often, within ourselves, closed up by our self fear. We are so crippled with this fear that we are not even able to go to the door, to let Him in. But Christ comes in anyway, into our hearts and lives, and gives us His peace.
The other thing this scene brings to my mind is that soon after this the early Church would likewise congregate behind closed doors of brothers' homes, for fear of the Jews, and then for fear of the Romans. Even after the Church was able to construct special architecture for their gatherings, they worshipped behind closed doors, especially as they entered into the liturgy of the Eucharist. "The doors, the doors" the deacon would call out, for the mystery of the Eucharist is a most solemn moment in the Christian life. It is only for the faithful, and we must attend to it with the wisdom of faith, and the reverence of the barefoot Moses before the burning bush.
In very important ways, this appearance in the closed room was a eucharistic appearance. And since I have used the word "appearance" a few times already, I hasten to make a vitally important clarification at this point. We call this one of the post-resurrection appearances. But we do not in any way mean this the way, say, a Gnostic might use the term "appearance." Our Lord Jesus, uncreated Creator of the very real world, and also true man, made of flesh and blood, truly enters a room that was closed. How did He do this? I often hear even well intentioned, believing, Catholics and Lutherans and such, explain that Christ was able to do this because of His "glorified body." Our Lord's body, just as ours after our own resurrection, can be described as glorified. We do not fully know what this means. Nevertheless, we confess this. However, the text in this case (John 20) is teaching us something else, I suggest. It is teaching us that Our Lord Jesus Christ is able to do things with His very real body which defy what the same flesh of someone else could do. This is because of the hypostatic union of His divine and human natures, and the full communication of their attributes. A good clue to this effect is the fact that He performed similarly paradoxical operations before His resurrection. When He does so, it does not deny His humanity, but displays His divine majesty (Formula of Concord VIII). Perhaps the best example is the fact that He truly and physically descended His Mother's birth canal, yet without opening her womb. Her womb was a closed room (clauso, as in the John 20 text.) Martin Chemnitz is not the only one to confess this, nor is Luther. Saint Gregory the Great makes this very comparison in the Divine Office at Matins for this Sunday. He preaches thus in Homily 26 on the Gospels:
The first query which presents itself to the mind regarding the Gospel reading is this: how could the Lord have had a real body after the resurrection when He could come in to the disciples though the doors were closed? But we must not expect a complete explanation of this phenomenon; for we must realize that there would be nothing to wonder at in the divine operations if they could be grasped by reason; nor is there any merit in a faith for which human reason provides proof. As for these works of our Redeemer which can in nowise be grasped of themselves, they should be pondered in relation to His other activity. Thus we shall see that we already accept facts that are even more wonderful, and this consideration will strengthen our faith in the marvels now confronting us. For example, the body of the Lord which came in to the disciples through closed doors was that same one which had come forth to mankind's gaze from the enclosed womb of the Virgin at the time of the Nativity. Is it so surprising, then, that after the Resurrection the eternal Victor came in through closed doors when, on coming as death's Victim, He came forth from the unopened womb of the Virgin?
So He enters the closed room of the gathered disciples, just as they need Him, not gnostically, but incarnationally. Just as He left the closed temple of His mother's womb, and thus entered this sinful world. Likewise, whenever His followers are gathered today, in fulfillment of His command to remember and proclaim His death, He comes to us, no more or less miraculously, and makes Himself truly present, according to both His divine and human natures. He comes, and He blesses us. In the Mass it is His words we hear as we gaze upon the sacred species, and the called and ordained celebrant gives us our Lord's peace.
Finally, how about the time? Our Lord blessed His disciples with His presence on the first day of the week. This is the day of new life. It is the day on which God in the beginning created life by means of the eternal Word. He said, Fiat. Let there be. His Word brings about what it declares, like "This is My Body," and "I forgive Thee," and "It is finished." Every appearance of Christ our Immanuel is eucharistic, for by His presence we are given a most salutary gift, and are shown the meaning of thanksgiving.