Imamat 18:8

18:8 You must not have sexual intercourse with your father’s wife; she is your father’s nakedness. ¹ 

Imamat 18:19

18:19 “‘You must not approach a woman in her menstrual impurity ²  to have sexual intercourse with her.

[18:8]  ¹ tn Heb “the nakedness of your father she is.” See the note on v. 7 above. This law refers to another wife of the man’s father, who is not that man’s mother. The laws in the Pentateuch sometimes assume the possibility that a man may have more than one wife (cf., e.g., Deut 21:15-17).

[18:19]  ² tn Heb “in the menstruation of her impurity”; NIV “during the uncleanness of her monthly period.”