Mark 6:19 (KJV)

For Herod himself had sent forth and laid hold upon John, and bound him in prison for Herodias’ sake, his brother Philip’s wife: for he had married her.

For John had said unto Herod, It is not lawful for thee to have thy brother’s wife.

Therefore Herodias had a quarrel against him, and would have killed him; but she could not:

For Herod feared John, knowing that he was a just man and an holy, and observed him; and when he heard him, he did many things, and heard him gladly.

And when a convenient day was come, that Herod on his birthday made a supper to his lords, high captains, and chief estates of Galilee;