Matthew 14:3-5

3For Herod had John arrested and bound him and put him in prison [at the fortress of Machaerus, east of the Jordan, to keep him away] because of Herodias, the wife of his brother Philip,

4for John had said to him, “It is not lawful (morally right) for you to have her [living with you as your wife].”

5Although Herod wished to have him put to death, he feared the people, for they regarded John as a prophet.