What does 1 Samuel 1:27 mean?

Hannah has brought her son Samuel to dedicate him to lifelong service to the Lord at the temple in Shiloh. She does so as fulfillment of a vow she made to the Lord if He would give her a son (1 Samuel 1:11, 22). The Lord did as she asked. Now she has come to hand her son Samuel, perhaps three or four years old (1 Samuel 1:14), into the keeping of the Lord and the priest Eli.

Hannah reminds Eli (1 Samuel 1:26) of the night a few years earlier when he found her praying to the Lord with such emotion and intensity that he thought she was drunk (1 Samuel 1:9–18). She tells him now that this boy, Samuel, is the child she prayed for. The text does not say that Hannah had earlier specified her petition to the Lord; she had only told Eli that she was pouring out her soul to the Lord and praying out of deep distress. Here she tells the priest that she had prayed for a child, and God has granted her request. She uses the same language that Eli used a few years prior: "The God of Israel grant your petition that you have made to him" (1 Samuel 1:17).

Whatever sadness Hannah may have felt at leaving the boy in Shiloh, she expresses only gratitude and joy at what the Lord has done for her.