Gregory the Dialogist

He looseth the belt of kings, and girdeth their reins with a cord. They that know how to regulate aright the motions of their members, are not unjustly called 'kings.' But when the mind is touched with pride on the grounds of that very continence, it very often happens that Almighty God, deserting its pride, suffers it to fall into uncleanness of practice. And so 'He looseth the belt of kings,' when in the case of those who seemed to regulate their members aright, on account of the sin of pride he undoes the girdle of chastity. …

Morals on the Book of Job, Book XI ↗

Thomas Aquinas

Since he has said this in a general way, he now makes it clear by specific examples, showing how all things which seem excellent in human affairs are brought by the depth of divine counsel "to a foolish end" and "to dullness." In human affairs, kings excel with respect to power. …

Commentary on Job ↗