Ezekiel 3:18

When I say unto the wicked The watchman spies danger approaching, so the prophet receives intimation from the Lord (Ezekiel 3:17). This intimation given to the prophet is represented as a threat spoken directly to the wicked. If the prophet as a watchman perceive this danger of death to the wicked and fails to warn him, the wicked shall die for his own sin indeed, but his blood will be upon the watchman. He that fails to save life kills; and blood will be required of him, of every man's hand the blood of his brother. Proverbs 24:11-12, "Deliver them that are carried away unto death … If thou sayest, Behold, we knew not this, Doth not he that weigheth the hearts consider it?"

in his iniquity Perhaps: throughhis iniquity. It is of the nature of sin that it is made the instrument of its own punishment, Job 8:4. "Warning" will naturally be of many kinds, suitable to those warned; some may be deterred and others allured from their evil.