1 Samuel 1:11-13

11And she vowed a vow, and said, O Yhwh of Armies, 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 Yhwh all the days of his life, and there shall no razor come upon his head.1

12And it came to pass, as she continued praying before Yhwh, that Eli marked her mouth.2

13Now Hannah, she spake in her heart; only her lips moved, but her voice was not heard: therefore Eli thought she had been drunken.