John Mark
Mark 6:17ESV·traditional attribution

For it was Herod who had sent and seized John and bound him in prison for the sake of Herodias, his brother Philip’s wife, because he had married her.

Matthew Henry Presbyterian @wholebiblehenry

Here is, I. The wild notions that the people had concerning our Lord Jesus, Mar 6:15. His own countrymen could believe nothing great concerning him, because they knew his poor kindred; but others that were not under the power of that prejudice against him, were yet willing to believe any thing rather than the truth - that he was the Son of God, and the...

Commenting on Mark 6:14-29

John Gill Reformed Baptist @doctorgill

For Herod himself had sent forth,.... Some of his guard, a detachment of soldiers, and laid hold upon John; who seized upon him, and took him up: and bound him in prison; in the castle of Machaerus: for Herodias' sake, his brother Philip's wife, for he had married her; whilst his brother was living, and who had had children by her; See Gill on Mat 14:3.