Vayikra 18:18-20

Orthodox Jewish Bible

¹⁸ Neither shalt thou take your wife’s achot (sister), to be a rival wife, to uncover her nakedness, beside the other in her lifetime.

¹⁹ Also thou shalt not approach unto an isha to uncover her nakedness, as long as she has her tumah from her period of niddah.

²⁰ Moreover thou shalt not lie carnally with thy neighbor’s wife. You shall not give your shikhvat zera to make tamei with her.