Genesis 30:3-8

3 Then she said, “Here is Bilhah, my maidservant. Sleep with her so that she can bear children for me and that through her I too can build a family.”

4 So she gave him her servant Bilhah as a wife. Jacob slept with her,

5 and she became pregnant and bore him a son.

6 Then Rachel said, “God has vindicated me; he has listened to my plea and given me a son.” Because of this she named him Dan.

7 Rachel’s servant Bilhah conceived again and bore Jacob a second son.

8 Then Rachel said, “I have had a great struggle with my sister, and I have won.” So she named him Naphtali.