Genesis 30:5

3She said, “Behold, my maid Bilhah. Go in to her, that she may bear on my knees, and I also may obtain children by her.”

4She gave him Bilhah her servant as wife, and Jacob went in to her.

5Bilhah conceived, and bore Jacob a son.

6Rachel said, “God has judged me, and has also heard my voice, and has given me a son.” Therefore she called his name Dan.

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