Did Herod want John the Baptist dead, or was it Herodias while Herod protected him?

Both wanted it at one time or another, and Mark explains why Herod held back. Herod had arrested John because John condemned his marriage to Herodias, his brother Philip’s wife (Matthew 14:3–4; Mark 6:17–18). Matthew says that Herod, ‘wishing to kill him’ (Greek thelōn auton apokteinai), was afraid of the crowds, who counted John a prophet (Matthew 14:5). Mark says that Herodias “would have killed him; but she could not”, because Herod feared John, “knowing that he was a just man and an holy, and observed him”, that is, kept him safe (Greek synetērei), and “heard him gladly” (Mark 6:19–20).

These are two sides of a man pulled two ways. John’s rebuke stung, and Herod would have been glad to be rid of him; but he feared the people, he feared John himself, and he was drawn to his preaching. Herodias had no such doubts. She nursed her grudge and waited for her chance, which came at Herod’s birthday feast, when Herod’s rash oath to her daughter let her ask for John’s head. Both Gospels then say that the king was sorry, but would not break his oath before his guests (Matthew 14:9; Mark 6:26). Matthew gives the short version; Mark shows why Herod hesitated so long.

Josephus’ account

The Jewish historian Josephus, writing about AD 93, says that Herod put John to death because he feared that John’s great influence over the people might lead to a revolt (Antiquities 18.5.2). That fits Matthew’s note that Herod had his own reasons to want John dead, and that the people stood behind John.