15 And she said to her, Is it [too] little that thou hast taken my husband, that thou wilt take my son's mandrakes also? And Rachel said, Therefore he shall lie with thee to-night for thy son's mandrakes. 16 And when Jacob came from the fields in the evening, Leah went out to meet him, and said, Thou must come in to me, for indeed I have hired thee with my son's mandrakes. And he lay with her that night.
Matthew Henry's Commentary on Genesis 30:15-16
Commentary on Genesis 30:14-24
(Read Genesis 30:14-24)
The desire, good in itself, but often too great and irregular, of being the mother of the promised Seed, with the honour of having many children, and the reproach of being barren, were causes of this unbecoming contest between the sisters. The truth appears to be, that they were influenced by the promises of God to Abraham; whose posterity were promised the richest blessings, and from whom the Messiah was to descend.