Genesis 30:16-20

30:16 When Jacob came in from the fields that evening, Leah went out to meet him and said, “You must sleep with me because I have paid for your services with my son’s mandrakes.” So he had marital relations with her that night. 30:17 God paid attention to Leah; she became pregnant and gave Jacob a son for the fifth time. 30:18 Then Leah said, “God has granted me a reward because I gave my servant to my husband as a wife.” So she named him Issachar.

30:19 Leah became pregnant again and gave Jacob a son for the sixth time. 30:20 Then Leah said, “God has given me a good gift. Now my husband will honor me because I have given him six sons.” So she named him Zebulun.