Why Moses Had to Tell Aaron to Draw Near the Altar

1) (Vayikra 8:1) ("And the L–rd spoke to Moses, saying (Vayikra 8:2): "Take Aaron, and his sons with him, and the garments, and the oil of anointment, and the bullock of the sin-offering and the two rams and the basket of unleavened bread.") "Take Aaron and his sons with him": What is the intent of this? Because (Shemoth 32:35): "And the L–rd smote the people with plague because they had made the calf that Aaron had made" implies that Aaron was rejected, from "Take Aaron and his sons with him" all knew that he was (re-) accepted. Whence is it derived that Moses knew that Aaron was rejected? From (Devarim 9:20): "And against Aaron the L–rd was wroth to destroy him, and I prayed also on Aaron's behalf at that time," and it is not written there (as it is in the preceding verse in respect to Moses' prayer on behalf of Israel) "And the L–rd hearkened to me at that time too." From "Take Aaron and his sons with him," Moses knew that Aaron was (re-) accepted. Whence do we derive that it was in Aaron's heart that he had been rejected? It is written at the end of the episode (Vayikra 9:7) ("And Moses said to Aaron) draw near to the altar." (Why was this command necessary?) Had not Moses just presented to him the entire order of sacrifices? (We must say, then, that Moses saw Aaron hesitating, apparently feeling that his service would be rejected, and) to dispel this from his heart, he told him that the L–rd had said to him "Take Aaron and his sons with him," thus apprising Aaron that he had been (re-) accepted.