5 So then this Bridegroom, “fair in beauty above the children of men,” became deformed that He might make His Spouse fair to whom it is said, “O you beauteous among women,” of whom it is said, “Who is this that comes up, whitened” with the brightness of light, not the colouring of falsehood! He then who called them to the wedding, found a man who had not a wedding garment, and He said unto him, “Friend, how did you come in hither, not having a wedding garment? And he was speechless.”
For he found not what to answer. And the Master of the house Who had invited him said, “Bind him hands and feet, and cast him into outer darkness; there shall be weeping and gnashing of teeth.” For so small a fault, so great a punishment? For great it is. It is called a small fault not to have “the wedding garment;” small, but only by those who do not understand. How would He have been so incensed, how would He have so judged, to cast him, on account of the wedding garment which he had not, “bound hands and feet into outer darkness, where was weeping and gnashing of teeth,” unless it had been a very grievous fault, not to have “the wedding garment”?
I say this; seeing you have been invited through me; for though He invited you, He invited you by my ministry. You are all at the feast, have the wedding garment. I will explain what it is, that you may all have it, and if any one now hears me who has it not, let him, before the Master of the house comes and inspects His guests, be changed for the better, let him receive “the wedding garment,” and so sit down in all assurance.
Source: Sermons on Selected Lessons of the New Testament (New Advent)