1 Samuel 1:4-5, 11

And when the time was that Elkanah offered, he gave to Peninnah his wife, and to all her sons and her daughters, portions: but unto Hannah he gave a worthy portion; for he loved Hannah: but the LORD had shut up her womb.

And she vowed a vow, and said, O LORD of hosts, if thou wilt indeed look on the affliction of thine handmaid, and remember me, and not forget thine handmaid, but wilt give unto thine handmaid a man child, then I will give him unto the LORD all the days of his life, and there shall no razor come upon his head.