Leviticus 18:18-20

The Voice

¹⁸ As long as your wife is living, do not marry her sister or have sexual relations with her. This would make them rivals.

¹⁹ You are not to have sexual relations with a woman while she is in her menstrual impurity. ²⁰ Do not have sexual relations with your neighbor’s wife; such an act defiles you both.