Albert Barnes Commentary 1 Samuel 2:11

"And Elkanah went to Ramah to his house. And the child did minister unto Jehovah before Eli the priest." — 1 Samuel 2:11 (ASV)

The word “minister” is used in three senses in Scripture:

1. Of the service or ministration of both priests and Levites rendered to the Lord (Exodus 28:35, 43).
2. Of the ministrations of the Levites as rendered to the priests to aid them in divine service (Numbers 3:6).
3. Of any service or ministration, especially one rendered to a man of God, such as that of Joshua to Moses (Numbers 11:28).

The application of this term to Samuel, as ministering to the Lord before Eli the priest, accords “most exactly” with Samuel’s condition as a Levite.