Ezekiel 9:4, 6

And Jehovah said unto him, Go through the midst of the city, through the midst of Jerusalem, and set a mark upon the foreheads of the men that sigh and that cry over all the abominations that are done in the midst thereof.

slay utterly the old man, the young man and the virgin, and little children and women; but come not near any man upon whom is the mark: and begin at my sanctuary. Then they began at the old men that were before the house.