And you shall anoint Aaron and his sons refers back to what has already been said in 28.41; 29.7,21. Good News Translation interprets the And as “Then,” to suggest that this act should follow the anointing of the tabernacle and its furnishings. This is indeed the sequence indicated in 40.9-15. And consecrate them, literally “and you [singular] shall make them holy,” is also mentioned in 28.41 and 40.13. That they may serve me as priests, literally “to priest to [or, for] me,” is discussed at 28.1.

Quoted with permission from Osborn, Noel D. and Hatton, Howard A. A Handbook on Exodus. (UBS Helps for Translators). New York: UBS, 1999. For this and other handbooks for translators see here .