Charles Ellicott Commentary Leviticus 16:9

"And Aaron shall present the goat upon which the lot fell for Jehovah, and offer him for a sin-offering." — Leviticus 16:9 (ASV)

The goat upon which the Lord’s lot fell. —Immediately after the lots decided the destiny of the two goats, they were distinguished from each other by peculiar marks. The one which was “for Jehovah” had a red woolen thread tied around its neck, while the one “for Azazel” had the scarlet thread tied on its head or on its horns.

And offer him for a sin offering. —Better, and shall present it, or appoint it for a sin offering , as the actual offering of it took place afterwards .