Augustine of Hippo

You do not know when that last hour is going to come and yet you say, "I am reforming." When are you going to reform? When are you going to change? "Tomorrow," you say. Behold, how often you say, "Tomorrow, tomorrow." You have really become a crow. Behold, I say to you that when you make the noise of a crow, ruin is threatening you. For that crow whose cawing you imitate went forth from the ark and did not return.

Sermons On The Liturgical Season 224.4 ↗

Bede

He went out and returned, until the waters were dried up from the earth. It does not say he went out and returned to the ark; but he went out and returned, it says, until the waters were dried up from the earth, because obviously he was turning here and there with uncertain flight, now beginning to go away, now returning as if about to enter the ark, but not really seeking the window he had left, but rather wandering outside until, the waters being removed, he would find rest and a place for himself outside the ark; his going out and …

Commentary on Genesis (Hexaemeron) ↗

Gregory of Elvira

For what it says that the raven sent out from the ark would no more return, this showed that the impure pleasures of men must be expelled from the Church and are to return no further. For the raven signified the pleasures of the deceitful and impure soul, and the infamy of its black color showed the unrighteous vice of sinners.

On The Ark Of Noah 25 ↗