1 Samuel 1:3, 11

Each year Elkanah would travel to Shiloh to worship and sacrifice to the LORD of Heaven’s Armies at the Tabernacle. The priests of the LORD at that time were the two sons of Eli—Hophni and Phinehas.

And she made this vow: “O LORD of Heaven’s Armies, if you will look upon my sorrow and answer my prayer and give me a son, then I will give him back to you. He will be yours for his entire lifetime, and as a sign that he has been dedicated to the LORD, his hair will never be cut.”