Clement of Alexandria

Now, it is a very great thing to abandon opinion, by taking one's stand between accurate knowledge and the rash wisdom of opinion, and to know that he who hopes for everlasting rest knows also that the entrance to it is toilsome "and strait." And let him who has once received the Gospel, even in the very hour in which he has come to the knowledge of salvation, "not turn back, like Lot's wife," as is said; and let him not go back either to his former life, which adheres to the things of sense, or to heresies. …

The Stromata Book 7 ↗

Cyprian

It was my duty not to conceal these special matters, nor to hide them alone in my own consciousness,-matters by which each one of us may be both instructed and guided. And do not you for your part keep this letter concealed among yourselves, but let the brethren have it to mad. For it is the part of one who desires that his brother should not be warned and instructed, to intercept those words with which the Lord condescends to admonish and instruct us. …

Epistle VII ↗

Ancient Greek Expositor

For the frequent looking upon the things which we have forsaken, through the force of habit draws us back to our past way of life. For practice has great power to retain to itself. Is not habit generated of use, and nature of habit? But to get rid of or change nature is difficult; for although when compelled it for a while turns aside, it very rapidly returns to itself.

Catena Aurea by Aquinas ↗

Bede

And Jesus said to him: No man, having put his hand to the plow, and looking back, is fit for the kingdom of God. To put one's hand to the plow, is as if with a kind of instrument of compunction, with wood and iron to grind down the hardness of one's heart in the passion of the Lord, and open it to bring forth the fruits of good works. If anyone, having begun to cultivate this, in delight looks back at the vices he left behind with Lot's wife, he is deprived of the gift of the future kingdom.

On the Gospel of Luke ↗

Bonaventure

Second, with regard to the rebuke of inconstancy, he adds: Jesus said to him: No one putting his hand to the plow, etc., that is, to the exercise of divine perfection and preaching, which is rightly designated by the plow on account of its cultivation and fruit, according to that passage in Hosea 10: "Judah shall plow, and Jacob shall break his furrows." No one, I say, being such, and looking back, that is, toward the world, is fit for the kingdom of God, that is, for possessing the kingdom of God: because, according to that passage …

Commentary on Luke, Chapter 9 ↗