{For the sake of Herodias} (dia H(8872)(9369)diada). The death of
John had taken place some time before. The Greek aorists here
(ed(8873)en, apetheto) are not used for past perfects. The Greek
aorist simply narrates the event without drawing distinctions in
past time. This Herodias was the unlawful wife of Herod Antipas.
She was herself a descendant of Herod the Great and had married
Herod Philip of Rome, not Philip the Tetrarch. She had divorced
him in order to marry Herod Antipas after he had divorced his
wife, the daughter of Aretas King of Arabia. It was a nasty mess
equal to any of our modern divorces. Her first husband was still
alive and marriage with a sister-in-law was forbidden to Jews
( Le 18:16 ). Because of her Herod Antipas had put John in the
prison at Machaerus. The bare fact has been mentioned in  Mt
4:12  without the name of the place. See  11:2  also for the
discouragement of John en t(9369) desm(9374)(8872)i(9369) (place of bondage),
here en t(8869) phulak(8869) (the guard-house). Josephus (_Ant_. xviii.
5.2) tells us that Machaerus is the name of the prison. On a high
hill an impregnable fortress had been built. Tristram (_Land of
Moab_) says that there are now remains of "two dungeons, one of
them deep and its sides scarcely broken in" with "small holes
still visible in the masonry where staples of wood and iron had
once been fixed. One of these must surely have been the
prison-house of John the Baptist." "On this high ridge Herod the
Great built an extensive and beautiful palace" (Broadus). "The
windows commanded a wide and grand prospect, including the Dead
Sea, the course of the Jordan, and Jerusalem" (Edersheim, _Life
and Times of Jesus_).