Charles Ellicott Commentary Leviticus 16:10

"But the goat, on which the lot fell for Azazel, shall be set alive before Jehovah, to make atonement for him, to send him away for Azazel into the wilderness." — Leviticus 16:10 (ASV)

On which the lot fell to be the scapegoat. —Better, on which the lot “for Azazel” fell. This one with its distinctive scarlet badge was placed at the spot from where he was sent away, and thus stood alive, not presented, before the Lord.

To make an atonement with him. —Better, to make atonement for it, that is, it was placed before the Lord in order that it might receive expiation and sanctification, and thus be fitted for the sacred purposes it was destined to fulfill. (Leviticus 16:18.)

And to let him go for a scapegoat into the wilderness. —Better, to send it to Azazel into the wilderness.