16 It is said, and it is true, and no deceiving saying, “Knock, and it shall be opened unto you;” but now when it is the time of mercy, not when it is the time of judgment. For these times cannot be confounded, since the Church sings to her Lord of “mercy and judgment.” It is the time of mercy; repent. Can you repent in the time of judgment? You will be then as those virgins, against whom the door was shut. “Lord, Lord, open to us.” What! Did they not repent, that they had brought no oil with them? Yes, but what profits them their late repentance, when the true wisdom mocked them? Therefore “the door was shut.” And what was said to them? “I know you not.” Did not He know them, who knows all things? What then is, “I know you not?” I refuse, I reject you. In my art I do not acknowledge you, my art knows not vice; now this is a marvellous thing, it does not know vice, and it judges vice. It does not know it in the practice of it; it judges by reproving it. Thus then, “I know you not.”
Source: Sermons on Selected Lessons of the New Testament (New Advent)