Exodus 40:23-29

Moses performed these priestly functions (Exodus 28:1 note), before the holy things with which they were performed were anointed. The things had been made expressly for the service of Yahweh, by His command, and in this fact lay their essential sanctity, of which the anointing was only the seal and symbol. Aaron and his sons, on similar ground, having had the divine call, took part in the service of the sanctuary as soon as the work was completed Exodus 40:31. But Moses took part with them, and most likely took the lead, until they were consecrated and invested Leviticus 8 and publicly set apart for the office.

Exodus 40:26

Before the vail - That is, opposite to the ark, in the middle between the table of showbread on the North and the candlestick on the South.