What does 1 Samuel 1:25 mean?

Hannah (and likely Elkanah) have arrived at the temple in Shiloh to dedicate their son Samuel to a life of service to the Lord and to leave him with Eli at the temple (1 Samuel 1:11, 21–23). They have brought with them a generous sacrifice that includes either a three-year old bull or three bulls, depending on the reading of the Hebrew, along with flour and wine (1 Samuel 1:24).

After the bull was slaughtered for the sacrifice to the Lord, Hannah and Elkanah brought the young boy to Eli, the high priest of Israel at Shiloh (1 Samuel 1:9), where the ark of the covenant rested (Joshua 18:1).

Hannah and Eli had met at least once before when she came in deep distress to the temple to pour out her soul to the Lord and offer her vow to Him. Hannah had been barren and her husband's second wife, who had children, intentionally tormented her (1 Samuel 1:2, 6–10). Hannah brought her request for a child to the Lord, promising that if He gave her a son, she would give that son to the Lord for his whole life (1 Samuel 1:11). Seeing Hannah in prayer, with her lips moving yet no words coming from her mouth, Eli had assumed she was drunk. He confronted her, and Hannah explained that she was not drunk but was praying. Eli blessed her, affirmed her prayer, and possibly even told her that God would grant her request (1 Samuel 1:12–18).