And it came to pass on the {a} eighth day, that Moses called Aaron and his sons, and the elders of Israel;

(a) After their consecration: for the seven days before, the priests were consecrated.

Wesley's Notes

9:1 On the eighth day - Namely, from the day of his consecration, or when the seven days of his consecration were ended. The eighth day is famous in scripture for the perfecting and purifying both of men and beasts. See Lev 12:2,3 14:8,9,10 15:13,14 22:27. And the elders of Israel - All the congregation were called to be witnesses of Aaron's installment into his office, to prevent their murmurings and contempt; which being done, the elders were now sufficient to be witnesses of his first execution of his office.

Jamieson-Fausset-Brown Bible Commentary

CHAPTER 9

Le 9:1-24. The Priests' Entry into Office.

1-7. Moses called . Take thee a young calf for a sin offering-The directions in these sacred things were still given by Moses, the circumstances being extraordinary. But he was only the medium of communicating the divine will to the newly made priests. The first of their official acts was the sacrifice of another sin offering to atone for the defects of the inauguration services; and yet that sacrifice did not consist of a bullock-the sacrifice appointed for some particular transgression, but of a calf, perhaps not without a significant reference to Aaron's sin in the golden calf [Ex 32:22-24]. Then followed a burnt offering, expressive of their voluntary and entire self-devotement to the divine service. The newly consecrated priests having done this on their own account, they were called to offer a sin offering and burnt offering for the people, ending the ceremonial by a peace offering, which was a sacred feast. This injunction, "to make atonement for himself and for the people" (Septuagint, "for thy family"), at the commencement of his sacred functions, furnishes a striking evidence of the divine origin of the Jewish system of worship. In all false or corrupt forms of religion, the studied policy has been to inspire the people with an idea of the sanctity of the priesthood as in point of purity and favor with the Divinity far above the level of other men. But among the Hebrews the priests were required to offer for the expiation of their own sins as well as the humblest of the people. This imperfection of Aaron's priesthood, however, does not extend to the gospel dispensation: for our great High Priest, who has entered for us into "the true tabernacle," "knew no sin" (Heb 10:10, 11).

Matthew Henry's Concise Commentary

9:1-21 These many sacrifices, which were all done away by the death of Christ, teach us that our best services need washing in his blood, and that the guilt of our best sacrifices needs to be done away by one more pure and more noble than they. Let us be thankful that we have such a High Priest. The priests had not a day's respite from service allowed. God's spiritual priests have constant work, which the duty of every day requires; they that would give up their account with joy, must redeem time. The glory of God appeared in the sight of the people, and owned what they had done. We are not now to expect such appearances, but God draws nigh to those who draw nigh to him, and the offerings of faith are acceptable to him; though the sacrifices being spiritual, the tokens of the acceptance are spiritual likewise. When Aaron had done all that was to be done about the sacrifices, he lifted up his hands towards the people, and blessed them. Aaron could but crave a blessing, God alone can command it.