Augustine of Hippo

"Lord, my heart is not lifted up" [Psalm 131:1]. He hath offered a sacrifice. Whence do we prove that he hath offered a sacrifice? Because humility of heart is a sacrifice. ...If there is no sacrifice, there is no Priest. But if we have a High Priest in Heaven, who intercedeth with the Father for us (for He hath entered into the Holy of Holies, within the veil), ...we are safe, for we have a Priest; let us offer our sacrifice there. …

Exposition on Psalm 131 ↗

Jerome

I know your humility. I know that you can say with sincerity, "Lord, my heart is not haughty or my eyes lofty"; I know that in your heart as in that of your mother the pride through which the devil fell has no place. It would be time wasted to write to you about it; for there is no greater folly than to teach a pupil what he knows already. But now that you have despised the boastfulness of the world, do not let the fact inspire you with new boastfulness. …

Letter 22.27 ↗

Hilary of Poitiers

This Psalm, a short one, which demands an analytical rather than a homiletical treatment, teaches us the lesson of humility and meekness. Now, as we have in a great number of other places spoken about humility, there is no need to repeat the same things here. Of course we are bound to bear in mind in how great need our faith stands of humility when we hear the Prophet thus speaking of it as equivalent to the performance of the highest works: O Lord, my heart is not exalted. …

Homilies on the Psalms, Psalm 131 ↗