And some of the sons of the priests made the ointment of the spices. The sons of the priests made the ointment - Only the priests were permitted to make this ointment; all others were forbidden to do it on pain of death; see Exodus 30:34-38 (note), and the notes there.
Related Commentaries of 1 Chronicles 9:30
1 Chronicles 9:30
30 And some of the sons of the priests made the ointment of the spices.