1 Samuel 1:3, 11

Now this man would go up from his city yearly to worship and to sacrifice to the LORD of hosts in Shiloh. And the two sons of Eli, Hophni and Phinehas, were priests to the LORD there.

She made a vow and said, “O LORD of hosts, if You will indeed look on the affliction of Your maidservant and remember me, and not forget Your maidservant, but will give Your maidservant a son, then I will give him to the LORD all the days of his life, and a razor shall never come on his head.”