John Chrysostom

"Wherefore let him that thinketh he standeth take heed lest he fall." Again, he casts down their pride who thought highly of their knowledge. For if they who had so great privileges suffered such things; and some for murmuring alone were visited with such punishment, and others for tempting, and neither their multitude moved God to repent, nor their having attained to such things; much more shall it be so in our case, except we be sober. …

Homily on 1 Corinthians 23 ↗

Theophylact of Ohrid

Again he hints at those who were greatly puffed up by their knowledge. Although you think that you stand, nevertheless take heed lest you fall. For your very confidence that you stand shows that you do not stand. It seems so to you, but in reality you do not stand. But even if you do stand, through pride you can easily fall.

Commentary on 1 Corinthians ↗

Cyprian

Moreover, we do not prejudge when the Lord is to be the judge; save that if He shall find the repentance of the sinners full and sound, He will then ratify what shall have been here determined by us. If, however, any one should delude us with the pretence of repentance, God, who is not mocked, and who looks into man's heart, will judge of those things which we have imperfectly looked into, and the Lord will amend the sentence of His servants; while yet, dearest brother, we ought to remember that it is written, "A brother that helpeth …

Epistle LI ↗

Bonaventure

Because humility is the dwelling place of grace, the grace of the Holy Spirit rests upon the humble alone. Whence Augustine, in the third book of On Christian Doctrine: "For this reason the sins of great men were written down, so that that apostolic saying might everywhere be feared: Wherefore let him who seems to stand take heed lest he fall. For there is no page of the holy books in which it does not resound: God resists the proud, but to the humble He gives grace."

Disputed Questions on Evangelical Perfection, Question 1 ↗