Gregory of Nyssa — as excerpted in the Catena Aurea on Luke 12:35-40

“(Hom. 11. in Cant..) Or else, when the wedding was celebrated and the Church received into the secret bridal chamber, the angels were expecting the return of the King to His own natural blessedness. And after their example we order our life, that as they living together without evil, are prepared to welcome their Lord’s return, so we also, keeping watch at the door, should make ourselves ready to obey Him when He comes knocking; for it follows, that when he cometh and knocketh, they may open to him immediately.”