Seeing as Moshe was commanded (Sh'mos 40:9-15) to anoint the Mishkan and its Kelim, and only afterwards to bathe, dress and anoint Aharon and his sons, why did he bathe and dress them before anointing the Mishkan and its Keilim?
Ramban and Moshav Zekenim: There, the Torah wanted to discuss the actions to Aharon and his sons together. Really, he did like it says here; it was correct for Aharon and his sons to be ready to be anointed immediately after anointing the Mishkan and its Keilim.
Oznayim la'Torah: Since Moshe had already prepared the Mishkan for the inauguration, but not Aharon and his sons, he now prepared Aharon and his sons too ? and then went on to anoint the Mishkan and its Keilim before Aharon and his sons 1 (as per instructions).
Oznayim la'Torah: Because before the Mishkan was anointed there was no point in anointing Aharon and his sons, due to the principle 'Ein Kihun be'Bamah' ('There is no Din of Kehunah by a Bamah').
