And she gave him Bilhah her handmaid as his wife: and Jacob went in unto her.
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Ephrem The Syrian
So, lest she nag him, asking him every day for children, Jacob, who was sent from his parents to take a daughter of Laban, agreed to take the foreign woman. But it was also so that the sons of the maidservants might become joint heirs with sons of the freewomen that Jacob took maidservants and freewomen. So he took Bilhah, and she conceived and bore Dan and Naphtali. .
Marriage. The Manichees condemned Jacob for having four wives at once. But St. Augustine replied, it was not then unusual or forbidden. He took the two last only at the pressing instigation of Rachel and Lia, and that only for the sake of children. Lia herself was forced upon him. (contra Faust. xxii. 48.)