Herod was the one who had John the Baptist arrested and bound in prison on account of Herodias, the wife of his brother Philip, whom he had married. John had said to Herod, “It is not lawful for you to have your brother’s wife.” Mark 6:17–19
Herod the tetrarch heard of the reputation of Jesus and said to his servants, “This man is John the Baptist. He has been raised from the dead; that is why mighty powers are at work in him.” Matthew 14:1–2
Herod feared John, knowing him to be a righteous and holy man, and kept him in custody. When he heard him speak he was very much perplexed, yet he liked to listen to him. Mark 6:20