Luke 22:12

Now in the upper parts he has a large room furnished, that you may consider how great were his merits in whom the Lord could sit down with His disciples, rejoicing in His exalted virtues.

Let us then ascend with the Lord united to us, to the upper part in which is the guestchamber, which is shown by the understanding, that is, the goodman of the house, to every one of the disciples of Christ. But this upper room of our house must be large enough to receive Jesus the Word of God, who is not comprehended but by those who are greater in comprehension. And this chamber must be made ready by the goodman of the house, (that is, the understanding,) for the Son of God, and it must be cleaned, wholly purged of the filth of malice. The master of the house also must not be any common person having a known name. Hence He says mystically in Matthew, Go ye to such a one.

Now on the same fifth day He sends two of His disciples to prepare the Passover, namely, Peter and John, the one in truth as loving, the other as loved. In all things showing, that even to the end of His life He opposed not the law. And He sends them to a strange house; for He and His disciples had no house, else would He have kept the Passover in one of them. So it is added, And they said, Where will thou that we prepare? He sends them for this reason to an unknown man: to show them that He voluntarily underwent His Passion, since He who so swayed the mind of one unknown to Him, that He should receive them, was able to deal with the Jews just as He wished. But some say that He gave not the name of the man, lest the traitor knowing his name might open the house to the Pharisees, and they should have come and taken Him before that the supper was eaten, and He had delivered the spiritual mysteries to His disciples. But He directs them by particular signs to a certain house; whence it follows, And ye shall say to the goodman of the house, The Master saith, Where is the guestchamber, &c. And he will show you an upper room, &c. By the day of unleavened bread, we must understand that conversation which is wholly in the light of the Spirit, having lost all trace of the old corruption of Adam's first transgression. And living in this conversation, it becomes us to rejoice in the mysteries of Christ. Now these mysteries Peter and John prepare, that is, action and contemplation, fervid zeal and peaceful meekness. And these preparers a certain man meets, because in what we have just mentioned, lies the condition of man who was created after the image of God. And he carries a pitcher of water, which signifies the grace of the Holy Spirit. But the pitcher is humbleness of heart; for He giveth grace to the humble, who know themselves to be but earth and dust.