As he hath done this day, so the Lord hath commanded to do,.... The same were to be repeated every day until the seven days were ended; so Jarchi and Aben Ezra; the former of these observes, that their Rabbins explain the phrase "to do", in the preceding clause, of the business of the red heifer, and that which follows:
to make an atonement for you, of the business of the day of atonement; and say, that it may be learned from hence that the high priest was obliged to be separate (from his own house and family) seven days before that, and so the priest that burned the red heifer; and the same is observed by other Jewish writers (d): but this refers to neither of these cases, but to the present consecration of Aaron and his sons, and the making atonement by sacrifice for them, and the sanctification of them to minister in the priest's office.
(d) Maimon, & Bartenora in Misn. Yoma, c. 1. sect. 1. & in Parah, c. 3. sect. 1.