Genesis 29:30-34

So Jacob had relations with Rachel also, and indeed he loved Rachel more than Leah, and he served with Laban for another seven years.

Now the Lord saw that Leah was unloved, and He opened her womb, but Rachel was unable to have children.

Leah conceived and gave birth to a son, and named him Reuben, for she said, “Because the Lord has seen my affliction; surely now my husband will love me.”

Then she conceived again and gave birth to a son, and said, “Because the Lord has heard that I am unloved, He has therefore given me this son also.” So she named him Simeon.

And she conceived again and gave birth to a son, and said, “Now this time my husband will become attached to me, because I have borne him three sons.” Therefore he was named Levi.