Genesis 30:3-8

So she said, “Here is my maid Bilhah; go in to her, and she will bear a child on my knees, that I also may have children by her.” Then she gave him Bilhah her maid as wife, and Jacob went in to her. And Bilhah conceived and bore Jacob a son. Then Rachel said, “God has judged my case; and He has also heard my voice and given me a son.” Therefore she called his name Dan. And Rachel’s maid Bilhah conceived again and bore Jacob a second son. Then Rachel said, “With great wrestlings I have wrestled with my sister, and indeed I have prevailed.” So she called his name Naphtali.