Augustine of Hippo

"Let not the foot of pride come against me" [Psalm 36:11]. But now he said, The children of men shall put their trust under the shadow of Your wings: they shall be satiated with the fullness of Your House. When one has begun to be plentifully overflowed with that Fountain, let him take heed lest he grow proud. For the same was not wanting to Adam, the first man: but the foot of pride came against him, and the hand of the sinner removed him, that is, the proud hand of the devil. …

Exposition on Psalm 36 ↗

Ambrose of Milan

"Let not the foot of pride come to me", that is, let me not fall into pride. Finally, elsewhere he remembers himself, saying: "If I have not walked in greatness." Here he prayed, there he fulfilled: he would not have fulfilled, if he had not prayed. Pride must be avoided, for it even trips one up in prosperity. Finally, Adam fell more heavily in paradise than if he had fallen on earth. To fall from great heights is a precipice: to slip on level ground, it is called a stumble. …

Commentaries on the Twelve Davidic Psalms, On Psalm 36, 26 ↗

Thomas Aquinas

For himself he asks two things. First he asks to be preserved from sin, and this by removing two causes of sin. One is interior: and this is pride, which is the beginning of all sin; hence he says, "Let not the foot of pride come to me," that is, let the desire to be proud be removed from me: Sir. 23: "Do not give me the haughtiness of the eyes." The other cause is exterior, when someone is incited by another to sin: Ps. …

Exposition on the Psalms of David ↗