Ezekiel 9:4, 5-6

and YAHWEH said to him, “Go throughout Jerusalem, and place a mark on the foreheads of all who grieve and are greatly distressed over all the disgusting things done in the city.”

And I heard him say to the other six, “Follow the man in white linen through the city and strike down everyone with no mark on their forehead—old men, young men, girls, children, women—kill them all. Show no mercy, not even one glance of pity. But do not touch anyone with a mark on his forehead. And begin at my sanctuary.” So, they began with those men in front of the temple and with the elders.