Matthew 14:9-10 - And the king was sorry: nevertheless for the oath’s sake, and them which sat with him at meat, he commanded it to be given her. And he sent, and beheaded John in the prison.
Herodias had few equals in immorality and cruelty. She had been planning to get rid of John from the very first time she heard his rebuke of adultery. She waited for the right time, which presented itself when Herod’s birthday was kept. She had her daughter dance before those at the party, which pleased Herod. She was so hateful, vengeful, and wicked that she had no problem recruiting her own daughter to perform a lewd dance before her stepfather and his guests, which resulted in the beheading of John the Baptist.
Because he was in a gluttonous, lustful stupor Herod was easily taken in by his evil wife and stepdaughter. He had lost all dignity, all sensibility, and what little desire to do what was right he may have had. Wanting to appear the magnanimous benefactor before his guests, he had boxed himself in and was now completely vulnerable to his conniving wife.
Although he was sorry: nevertheless for the oath’s sake, he beheaded John in the prison. He may have been sorry, but his sorrow had nothing to do with remorse for sin or with genuine repentance. Even drunk, he knew he had been tricked; but his pride would not let him do what was right. Instead of admitting the stupidity of his foolish promise, he let himself be used to commit murder - all to save a reputation he did not have. With the help of Herodias and her daughter, his cup of iniquity was filled.