17 For Herod himself had sent and laid hold of John, and bound him in prison for the sake of Herodias, his brother Philip's wife; because he had married her.
Mark 6:17 Cross References - CAB
Matthew 4:12
12 Now when Jesus heard that John had been imprisoned, He departed into Galilee.
Matthew 11:2
2 And when John had heard in prison about the works of the Messiah, having sent two of his disciples,
Matthew 14:3-12
3 For Herod had laid hold of John and bound him, and put him in prison on account of Herodias, his brother Philip's wife.
4 For John said to him, "It is not lawful for you to have her."
5 Though desiring to kill him, he feared the crowd, because they counted him as a prophet.
6 Now when Herod's birthday was being celebrated, the daughter of Herodias danced before them, and she pleased Herod.
7 Therefore he promised with an oath to give her whatever she should ask.
8 So she, being urged on by her mother, said, "Give me here on a platter the head of John the Baptist."
9 And the king was grieved, but because of the oaths, and because of those who reclined to eat with him, he commanded it to be given.
10 And having sent, he beheaded John in the prison.
11 And his head was brought on a platter and it was given to the girl, and she brought it to her mother.
12 Then his disciples came forward and took the body and buried it, and coming, they reported it to Jesus.
Luke 3:1
1 Now in the fifteenth year of the reign of Tiberius Caesar, while Pontius Pilate was governing Judea, and while Herod governed as tetrarch of Galilee, and while Philip his brother governed as tetrarch of Iturea and the region of Trachonitis, and while Lysanias governed as tetrarch of Abilene,