And the king was exceeding sorry. We cannot suppose that this was a pretended grief. The true reason is doubtless to be found in the relentless animosity of Herodias. Herod must have known well that he could not be bound by his oath in reference to a petition so unreasonable and so iniquitous.
Nevertheless he thought that "the words of a king were law." St. Augustine says, "The girl dances; the mother rages. A rash oath is made amidst the excitement and the voluptuous indulgence of the feast; and the savage desires of Herodias are fulfilled."
For the sake of his oaths ( διὰ τοὺς ὅρκους); the plural shows that he repeated the rash promise once and again.