Gregory the Dialogist

But not without most deep wonder do I consider, that he who in his mother's womb was filled with the spirit of prophecy, than whom there arose not a greater among them that are born of women, is cast into prison by wicked men, and is beheaded because of the dancing of a girl, and that a man of such severe life dies for the sport of shameful men. Are we to think that there was any thing in his life which this so shameful death should wipe away? …

Catena Aurea by Aquinas ↗

Hilary of Poitiers

So among the other gratifications of a debauched people the head of John is brought in in a dish, that is by the loss of the Law, the pleasures of the body, and worldly luxury is increased. It is carried by the damsel to her mother; thus depraved Israel offered up the glory of the Law to pleasure and unbelief.

Catena Aurea by Aquinas ↗

Thomas Aquinas

And he sent and beheaded John. Here the execution is set forth. Here is fulfilled what he had said: he must increase, but I must decrease, because Christ was extended on the cross, while John was beheaded. Likewise, the beheading of John was a sign that by the authority of the law they were destined to lose both Christ and the law.

Commentary on Matthew ↗