Genesis 30:4-8

And she gave him Bilhah her handmaid to wife: and Jacob went in unto her.

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.