Genesis 30:5-9

And Bilhah conceived, and bare Jacob a son.

And Rachel said, God hath judged me, and hath also heard my voice, and hath given me a son: therefore called she his name Dan.

And Bilhah Rachel’s maid conceived again, and bare Jacob a second son.

And Rachel said, With great wrestlings have I wrestled with my sister, and I have prevailed: and she called his name Naphtali.

When Leah saw that she had left bearing, she took Zilpah her maid, and gave her Jacob to wife.