Genesis 30:4-8

So Rachel gave her servant, Bilhah, to Jacob as a wife, and he slept with her. Bilhah became pregnant and presented him with a son. Rachel named him Dan, for she said, “God has vindicated me! He has heard my request and given me a son.” Then Bilhah became pregnant again and gave Jacob a second son. Rachel named him Naphtali, for she said, “I have struggled hard with my sister, and I’m winning!”