Charles Ellicott Commentary 1 Chronicles 9:30

"And some of the sons of the priests prepared the confection of the spices." — 1 Chronicles 9:30 (ASV)

A parenthetical remark. The Levites had charge of the stores of spices, but only the priests could lawfully prepare the holy ointment and oil with which the sacred tent, the ark, the table, etc., were anointed (Exodus 30:23–29).