Genesis 30:14-18

14 During wheat harvest, Reuben went out into the fields and found some mandrake plants, which he brought to his mother Leah. Rachel said to Leah, “Please give me some of your son’s mandrakes.”

15 But she said to her, “Wasn’t it enough that you took away my husband? Will you take my son’s mandrakes too?”
“Very well,” Rachel said, “he can sleep with you tonight in return for your son’s mandrakes.”

16 So when Jacob came in from the fields that evening, Leah went out to meet him. “You must sleep with me,” she said. “I have hired you with my son’s mandrakes.” So he slept with her that night.

17 God listened to Leah, and she became pregnant and bore Jacob a fifth son.

18 Then Leah said, “God has rewarded me for giving my maidservant to my husband.” So she named him Issachar.