Verse 11: And Elkanah went to Ramah to his house. (1 Sam. 2:18; 3:1) And the child did minister unto the LORD before Eli the priest.
[To his house] Here, עַל/upon, in the place of אֶל/to (Drusius).
[Now, the child was a minister, etc.] Question: In what manner was he able to be a minister at that age? Responses: 1. In singing and playing musical instruments, with Eli himself asking it of him (Vatablus). So that he might sing divine praises with the other Levites in the Tabernacle (certain interpreters in Mendoza). Seeing that from him those sings sprung, concerning whom 1 Chronicles 6; 25 (Serarius). 2. Samuel was learning the law of God (Vatablus), and what things were pertaining to the ministry of the Temple; and he was beginning to do those things, to the extent that his youth would allow; as to keep the sanctuary, to light the lamps, etc. (Serarius out of Tostatus). The Master of history refers this ministry to the study of literature, which also other children studying, whom Samuel was nevertheless excelling in ability and zeal. But this was not the sacred ministry, but was pertaining also to the laity (Mendoza). 3. Perhaps the expression here does not concerning him in his youth age, but as already more mature (Sanchez). It is a Prolepsis. It does not speak of that time immediately after the departure of Hannah from the Tabernacle, but by anticipation of that time, in which Samuel by age was fit to minister (Mendoza). [4. Perhaps he was not as young as these suppose, when he was taken to the tabernacle, but more than seven or ten years old, concerning which see on 1 Samuel 1:23, 24.]
[In the sight of the Lord] Namely, in the Temple, where God is said to dwell in a peculiar manner (Mendoza, Tostatus).
The child did minister unto the LORD: In some way agreeable to his tender years, as in singing, or playing upon instruments of music, as they used then to do in God’s service; or lighting the lamps, or some other way. For I suppose Samuel was not brought to the tabernacle in such tender years as some think; of which see on 1 Samuel 1:22.
[Before the face of Eli, אֶת־פְּנֵ֖י עֵלִ֥י] Before (with the faces [Montanus], in the sight of [Syriac, Junius and Tremellius]) Eli (Septuagint, Piscator, Tigurinus, Vatablus, Drusius). It is a Hebraism for at the commandment of Eli, in those things that Eli was prescribing to him (Vatablus). אֶת־פְּנֵי is the same thing as לִפְנֵי, with the face, that is, before the face, in the sight of. Eli was his preceptor (Drusius).
Before Eli the priest, that is, under the inspection and by the direction and instruction of Eli.
 Hebrew: וַיֵּ֧לֶךְ אֶלְקָנָ֛ה הָרָמָ֖תָה עַל־בֵּית֑וֹ וְהַנַּ֗עַר הָיָ֤ה מְשָׁרֵת֙ אֶת־יְהוָ֔ה אֶת־פְּנֵ֖י עֵלִ֥י הַכֹּהֵֽן׃  Hebrew: עַל־בֵּיתוֹ.  1 Samuel 1:11b: “…And the child did minister unto the Lordוְהַנַּ֗עַר הָיָ֤ה מְשָׁרֵת֙) אֶת־יְהוָ֔ה; puer autem erat minister in conspectu Domini, now the child was a minister in the sight of God, in the Vulgate) before Eli the priest.”