And you shall not have a woman as a rival wife, who is the sister of your other wife, for this is to expose her nakedness while her sister, your other wife, is still alive.
Leah said to her, “Is it a small matter that you have taken my husband? Would you take away my son’s mandrakes also?” So Rachel said, “All right, he may lie with you tonight in exchange for your son’s mandrakes.”
You shall not have relations with a woman and her daughter, nor shall you have her son’s daughter or her daughter’s daughter, for this exposes the woman’s nakedness. They are all near relatives. It is depravity.
Did He not make them one, having a remnant of the Spirit? And why one? He seeks godly offspring. So take heed to your spirit, that you do not deal treacherously.