Genesis 30:1-5

And when Rachel saw that she bare Jacob no children, Rachel envied her sister; and said unto Jacob, Give me children, or else I die. And Jacob's anger was kindled against Rachel: and he said, Am I in God's stead, who hath withheld from thee the fruit of the womb? And she said, Behold my maid Bilhah, go in unto her; and she shall bear upon my knees, that I may also have children by her. And she gave him Bilhah her handmaid to wife: and Jacob went in unto her. And Bilhah conceived, and bare Jacob a son.