Jerome

And the Lord will scatter from Israel the head and the tail, the bend and the corrupt in one day. The venerable and honorable, he is the head; and the Prophet teaching falsehood, he is the tail. And there will be those who call this people blessed, deceiving, and those who are called blessed, being cast down. Therefore, the Lord will not rejoice over his young men, and will not have mercy on his orphans and widows, for every hypocrite is wicked, and every mouth has spoken foolishness. …

Commentary on Isaiah ↗

Gregory the Dialogist

Where the head and the tail are said through the prophet to be destroyed, it is clear that priests are designated by the head and prophets by the tail. The crown, therefore, is removed from the head when those who are seen to preside over the body of the church abandon the rewards of heavenly compensation. Once its leaders fall, normally, the army that follows them also succumbs. …

Morals on the Book of Job 14.43-44 ↗

Thomas Aquinas

315. The Lord shall destroy. Here he threatens against trust in the use of persons; and first, the punishment is set out; second, the preparation of further punishment: for all this (Isa 9:17). Now persons seemed useful either for defense, and against these he threatens first; or for provoking divine mercy, and he threatens against these where it says, therefore the Lord shall have no joy in their young men (Isa 9:17). Concerning the first, he does three things. …

Commentary on Isaiah ↗