Cross reference
Leviticus 22:12
12 And if the daughter of a priest is married to an outside person she may not take of the holy things which are lifted up as offerings.
Leviticus 21:3
3 And for his sister, a virgin, for she is his near relation and has had no husband, he may make himself unclean.
Isaiah 40:13
13 By whom has the spirit of the Lord been guided, or who has been his teacher?