“And Aharon shall make atonement upon its horns once a year with the blood of the sin offering of atonement – once a year he makes atonement upon it throughout your generations. It is most set-apart to יהוה.”
“And no man should be in the Tent of Meeting when he goes in to make atonement in the Set-apart Place, until he comes out. And he shall make atonement for himself, and for his household, and for all the assembly of Yisra’ĕ
“And he shall go out to the altar that is before יהוה, and make atonement for it. And he shall take some of the blood of the bull and some of the blood of the goat, and put it on the horns of the altar all around.
“On the tenth day of this seventh month is the Day of Atonement. It shall be a set-apart gathering for you. And you shall afflict your beings, and shall bring an offering made by fire to יהוה.
and it was slaughtered. And Mosheh took the blood, and put some on the horns of the altar all around with his finger, and cleansed the altar. And he poured the blood at the base of the altar, and set it apart, to make atonement for it.
So in every way He had to be made like His brothers, in order to become a compassionate and trustworthy High Priest in matters related to Elohim, to make atonement for the sins of the people.