Mark 6:17

For Herod himself had sent [guards] and had John arrested and shackled in prison because of Herodias, the wife of his [half-] brother Philip, because he (Herod) had married her.

Matthew 11:2

Now when John [the Baptist] in prison heard about the activities of Christ, he sent word by his disciples

Luke 3:19-20

But when Herod [Antipas] the tetrarch was repeatedly reprimanded [and convicted by John’s disapproval] for having Herodias, his brother’s wife [as his own], and for all the wicked things that Herod had done,

Matthew 4:12

Now when Jesus heard that John [the Baptist] had been arrested and put in prison, He left for Galilee.

Matthew 14:3-12

For 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,

Luke 3:1

Now in the fifteenth year of [Emperor] Tiberius Caesar’s reign—when Pontius Pilate was governor of Judea, and Herod [Antipas] was tetrarch of Galilee, and his brother Philip was tetrarch of the region of Ituraea and Trachonitis, and Lysanias was tetrarch of Abilene—

Treasury of Scripture Knowledge

Summary

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.

Philip's

General references

Bible References

Herod

Matthew 4:12
Now when Jesus heard that John [the Baptist] had been arrested and put in prison, He left for Galilee.
Matthew 11:2
Now when John [the Baptist] in prison heard about the activities of Christ, he sent word by his disciples
Matthew 14:3
For 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,
Luke 3:19
But when Herod [Antipas] the tetrarch was repeatedly reprimanded [and convicted by John’s disapproval] for having Herodias, his brother’s wife [as his own], and for all the wicked things that Herod had done,

Philip's

Luke 3:1
Now in the fifteenth year of [Emperor] Tiberius Caesar’s reign—when Pontius Pilate was governor of Judea, and Herod [Antipas] was tetrarch of Galilee, and his brother Philip was tetrarch of the region of Ituraea and Trachonitis, and Lysanias was tetrarch of Abilene—

General references

Leviticus 18:16
You shall not uncover the nakedness of your brother’s wife; it is your brother’s nakedness.
Luke 3:19
But when Herod [Antipas] the tetrarch was repeatedly reprimanded [and convicted by John’s disapproval] for having Herodias, his brother’s wife [as his own], and for all the wicked things that Herod had done,
John 3:24
for John had not yet been thrown into prison.