John Calvin on Matthew 22:11-13…
But when the king came in to see the guests, he saw a man there who did not have on a wedding garment. So he said to him, ‘Friend, how did you come in here without a wedding garment?’ And he was speechless. Then the king said to the servants, ‘Bind him hand and foot, take him away, and cast him into outer darkness; there will be weeping and gnashing of teeth.’
As to the wedding garment, is it faith, or is it a holy life? This is a useless controversy; for faith cannot be separated from good works, nor do good works proceed from any other source than from faith. But Christ intended only to state, that the Lord calls us on the express condition of our being renewed by the Spirit after his image; and that, in order to our remaining permanently in his house, we must put off the old man with his pollutions, (Colossians 3:9; Ephesians 4:22,) and lead a new life, that the garment may correspond to so honorable a calling.
John Calvin, Commentaries, vol. XVI, p. 174