Porta haec clausa erit...

Durandus in the 6th book of his Rationale, as he explains the Sacred Liturgy of the great feast.

...Introivit dico in uterum Virginis, quo accepit carnem nostram, et exivit per portam clausam in regionem nostram. De hac porta dixit Ezechiel: Porta haec clausa erit (Ezech 44), et exivit de mundo per portam auream, idest charitatem quia per crucem; majorem enim hac dilectionem nemo habet, ut animam suam ponat quis pro amicis suis (Ioan 14).

... He entered our world, I say, in the womb of the Virgin, from whom he took our flesh and from which he departed as through a closed door, of which the prophet Ezechiel spoke, Porta haec clausa erit, and he departed from it through the golden door, that is by His charity upon the Cross; for as the Evangelist says, greater love has no man than he who lays down his life for his friends.