1 Samuel 1:9-11

After they had eaten and drunk in Shiloh, Hannah rose. Now Eli the priest was sitting on the seat beside the doorpost of the temple of the LORD. She was deeply distressed and prayed to the LORD and wept bitterly. And she vowed a vow and said, “O LORD of hosts, if you will indeed look on the affliction of your servant and remember me and not forget your servant, but will give to your servant a son, then I will give him to the LORD all the days of his life, and no razor shall touch his head.”