As their superior, and God's high priest, Eli blessed them in God's name, and they received his blessing by faith, which made it effectual, 1 Samuel 2:21. Seed, i.e. a child, or rather children, as the event showed. For the loan which is lent to the Lord, or, for the petition, i.e. the thing desired, to wit, the child; which she, thy wife, asked of the Lord; or, for the Lord, as 1 Samuel 1:28, to whom accordingly she hath given them. And therefore as she asked him not so much for herself, for she seldom sees him, as for the Lord, to whose service she hath wholly devoted him; so now I pray that God would give you other children, for both your comfort and enjoyment.
Related Commentaries of 1 Samuel 2:20
1 Samuel 2:20
20 And Eli blessed Elkanah and his wife, and said, The LORD give thee seed of this woman for the loanc which is lent to the LORD. And they went unto their own home.