Charles Ellicott Commentary Ezekiel 21:29

"while they see for thee false visions, while they divine lies unto thee, to lay thee upon the necks of the wicked that are deadly wounded, whose day is come in the time of the iniquity of the end." — Ezekiel 21:29 (ASV)

See vanity unto thee. —“See” is used in the sense of the utterances of the “seer,” or prophet. The Ammonites also had false prophets among them.

Thee upon the necks of them that are slain.— Judah is to fall first, then Ammon immediately after, as it were, upon the necks of those already slain. The figure is taken from the battle, in which one warrior falls upon the body of him who fell before him.

When their iniquity shall have an end. —Not through repentance, but because it ceases of necessity with the death of the sinner.