Job 12:18

These words must not refer to the sons of Aaron, who did not live anymore at that time, but to priests such as Job himself and Melchizedek. If the narrative is about real and holy priests, how is it said that they are led away in amazement? Evidently, [they are led away] in order that they may be astonished and admire the prodigies that are brought agains the impious through the decision of God and through the godhead. And so Job proceeds to relate here the admirable things that through the power and will of God happen in the sea, among the nations, among the kings and the leaders, and among all those, who prevail with force, deal with weapons and are called to war. Therefore, he submits.

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. Now what is meant by 'a cord,' but sin? As Solomon says, His own iniquities shall take the wicked himself, and he shall be holden with the cords of his sins. And because fleshly gratification has its dominion in the 'reins,' the strict Judge of the conscience, Who 'looseth the belt of kings,' 'girdeth their reins with a cord,' that, when the girdle of chastity is undone, then the gratification of sin should have dominion over their members, so that those whom pride pollutes in secret, He may shew even publicly to be as abominable as they are.

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. As to them he says, "The belt," that is the swordbelt, "of kings he loosens," for their power is designated in their swordbelt, according to the Psalm 44, "Gird your sword upon your thigh, O mighty one" (v.4); "and he girds their loins with ropes," when they are led into captivity, in which he notes the complete failing of their power.