The marriage restrictions having been laid down, there follows in the five next verses the prohibition of five sexual impurities unconnected with marriage except by their subject-matter. The first is to approach unto a woman to uncover her nakedness, as long as she is put apart for her uncleanness, that is, either for seven days at the time of her ordinary illnesses (Leviticus 15:19), or any longer time that her illness might last (Leviticus 15:25), or for forty days after the birth of a man child (Leviticus 12:2-4), or for eighty days after the birth of a girl (Leviticus 12:5).
The penalty for the offense within the seven days is death if committed willfully (Leviticus 20:18); if fallen into unknowingly, a ceremonial penalty of seven days' uncleanness is incurred (Leviticus 15:24).
It is twice referred to by Ezekiel as a gross sin (Ezekiel 18:6; Ezekiel 22:10).