Gregory the Dialogist

Hence another prophet says concerning unclean spirits: Who said to your soul, Bow down that we may pass over. For the soul stands upright when it desires heavenly things, and is by no means bent toward the lowest things. But when malign spirits see it standing in its uprightness, they cannot pass through it. For their passing through is to scatter unclean desires upon it. …

Forty Gospel Homilies, Homily 31 ↗

Thomas Aquinas

Second, the punishment of their enemies: and I will put it in the hand of them that have oppressed you, and have said to your soul: bow down, under our power, treating you so basely, as mud that is trod upon: your people, O Lord, they have brought low: and they have afflicted your inheritance (Ps 93:5); behold they whose judgment was not to drink of the cup, shall certainly drink (Jer 49:12).

Commentary on Isaiah ↗

Bernard of Clairvaux

Why does he not know, unless because, bending himself down to these lowest and earthly things, he heaps up earth for himself? Assuredly he does not know, concerning those things which he commits to the earth, for whom he gathers them: whether for the moth that destroys, or for the thief that digs through; for the enemy that plunders, or for the fire that devours. …

Sermons on the Song of Songs, Sermon 80 ↗