Verse 20: And Eli (Gen. 14:19) blessed Elkanah and his wife, and said, The LORD give thee seed of this woman for the loan which is (1 Sam. 1:28) lent (or, petition which she asked) to the LORD. And they went unto their own home.
[And Eli blessed Elkanah] Namely, with God’s words, as His priest: for which reason they received this blessing in faith, as in 1 Samuel 1:17, and it was accomplished in the following verse (Piscator out of Junius). Question: How is it here said that Eli blessed Elkanah, since it is read that he previously (namely, in verse 11) returned to his house? Response: Understand that this was done be Eli, because of whom Samuel was dedicated to God, as often as Elkanah came to Shiloh (Lightfoot).
Eli blessed Elkanah and his wife: 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, verse 21.
[The Lord render seed to thee, יָשֵׂם֩ יְהוָ֙ה לְךָ֥ זֶ֙רַע֙] The Lord put (restore [Junius and Tremellius], give [Vatablus, Drusius]) to thee seed (Montanus, Piscator), that is, another child (Vatablus). Seed here is able to be taken of one, as in Genesis 4:25, or, which is closer to the truth, of many, as it is evident from the following verse, in which she receives multiple children from this blessing (Mendoza).
Seed, that is, a child, or rather children, as the event showed.
[For the loan which thou didst lend to the Lord,תַּ֚חַת הַשְּׁאֵלָ֔ה אֲשֶׁ֥ר שָׁאַ֖ל לַֽיהוָ֑ה] They render it variously, for the gift which thou gavest to the Lord (Arabic); for the loan, or thing loaned, which thou didst lend (he did lend [Pagnine], or, which was lent [English]) to Jehovah (Syriac, Septuagint, Pagnine). That is, in the place of Samuel, whom you both asked of the Lord (Vatablus). In the place of that seed sought by prayer, which, having been obtained, thou hadst returned to Jehovah (Junius and Tremellius). Now, these are not the words of Eli, but of the author, to be conjoined with the beginning of the verse (Junius). For the petition which he petitioned, or asked. Understanding, either he (English), or she (Dutch) (Hebrew: he: See a similar exchange of the feminine and masculine genders, Genesis 6:1; Exodus 31:14; Leviticus 2:8; and elsewhere [Dutch]), or both of you (Vatablus, Munster), to the Lord (Montanus, Piscator), or of the Lord (Tigurinus, Munster, Dutch): that is to say, she asked him not for herself or her own advantage, but so that she might dedicate him to the Lord (Dutch). Because of the petition, that is, because of the child petitioned, who was even now given and dedicated to God. Others: who was petitioned of the Lord, or who was asked and desired before the Lord (Dutch). In the place of the one obtained, whom she obtained for Jehovah (Piscator). In the place of the restitution of that which she asked of the Lord (Drusius).
For the loan which is lent to the Lord, or, for the petition, that is, 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.
[And they departed unto their own place, לִמְקֹמוֹ] Not לִמְקוֹמָם, to their place. Hannah appear to have been from another city (Drusius). Or the woman is understood under the man; and what is said to have been done by one spouse, is signified to have been done by both (Mendoza). Now, I think that that these things were mentioned previously, when the boy was first brought to Shiloh; and are related here by recapitulation: or (which is the same thing) that the past perfect is here put in the place of the pluperfect; which often happens: that is to say, Eli had already previously blessed Elkanah (Sanchez).
Verse 21: And the LORD (Gen. 21:1) visited Hannah, so that she conceived, and bare three sons and two daughters. And the child Samuel (1 Sam. 2:26; 3:19; Judg. 13:24; Luke 1:80; 2:40) grew before the LORD.
[Therefore, the Lord visited, etc., כִּי־פָקַד] For He visited; they understand, they returned, I say, to their home with joy, because Jehovah had visited, etc.; for they had believed Eli’s words, which he had added to that blessing concerning future offspring. Or the כִּי/for is superfluous (Vatablus). To visit here is taken in a positive sense, as in Genesis 21:1; Exodus 13:19; Jeremiah 15:15; Luke 7:16; elsewhere in a negative sense, Exodus 32:34; Leviticus 26:16; Numbers 14:18 (Mendoza). It is difficult to determine to what the causal conjunction כִּי/for is to be referred. And it does not appear to be able aptly to be referred to any of the preceding sentences. But it appears that it is to be referred to a sentence understood in the verb, he blessed; that is to say, Eli blessed Elkanah and Hannah, and that efficaciously. I prefer to translate it, and so; so that the outcome of the blessing that preceded might be indicated (Piscator).
Visited, to wit, in mercy, and with his blessing, as that word is used, Genesis 21:1; Exodus 13:19; Jeremiah 15:15; not in anger, as it is taken Exodus 32:34; Leviticus 26:16.
[And the boy Samuel was magnified before the Lord,וַיִּגְדַּ֛ל הַנַּ֥עַר שְׁמוּאֵ֖ל עִם־יְהוָֽה׃] And great he became (he grew [Jonathan, English, Tigurinus, Munster, Junius and Tremellius]; he was magnified [Septuagint, Osiander]) in the presence of the Lord (Montanus, Junius and Tremellius), in whose presence no one is great, except one that is great in righteousness and holiness (Mendoza). Others: before the Lord (Septuagint, Syriac, Dutch, English, Munster, Tigurinus); with the Lord (Drusius, Malvenda), that is, by the help and assistance of God, as in Genesis 4:1 (Drusius). Full of grace and the Holy Spirit, inasmuch as the Lord was with him (Malvenda). Others: And Samuel grew, ministering before the Lord (Jonathan, similarly Vatablus). He was growing up, and ministering before the Lord (Arabic); he grew great, that is, in stature of body, and in the wisdom and understanding of the mind (Dutch). In this manner John is called great, Luke 1:15, not in magnitude of body, but of soul. The extraordinary uprightness of Samuel among the impious sons of Eli is here commended. He stood in a slippery place, namely, in association with the wicked, yet he did not fall (Mendoza). He grew in age, wisdom, and grace, out of 1 Samuel 2:26 (Lapide).
Grew; not only in age and stature, but especially in wisdom and goodness, as Luke 1:15. Or, was magnified; or grew great, famous and acceptable, as 1 Samuel 2:26. Before the Lord; not only before men, who might be deceived, but in the presence and judgment of the all-seeing God.
 Hebrew: וּבֵרַ֙ךְ עֵלִ֜י אֶת־אֶלְקָנָ֣ה וְאֶת־אִשְׁתּ֗וֹ וְאָמַר֙ יָשֵׂם֩ יְהוָ֙ה לְךָ֥ זֶ֙רַע֙ מִן־הָאִשָּׁ֣ה הַזֹּ֔את תַּ֚חַת הַשְּׁאֵלָ֔ה אֲשֶׁ֥ר שָׁאַ֖ל לַֽיהוָ֑ה וְהָלְכ֖וּ לִמְקֹמֽוֹ׃  Hebrew: הַשְּׁאֵלָ֔ה אֲשֶׁ֥ר שָׁאַ֖ל.  John Lightfoot (1602-1675) was an English churchman and divine of such distinction and learning that he was invited to sit as a member of the Assembly of Divines at Westminster. He specialized in Rabbinic learning and lore. He brought that learning to bear in his defense of Erastianism in the Assembly and in his comments upon Holy Scripture. He had a long and distinguished career at Cambridge, serving as Master of Catharine Hall, and later as Vice-chancellor of the University.  Genesis 6:1, 2: “And it came to pass, when men began to multiply on the face of the earth, and daughters were born unto them, that the sons of God saw the daughters of men that they were fair; and they took them wives of all (מִכֹּל, masculine) which they chose.”  Exodus 31:14: “Ye shall keep the sabbath (אֶת־הַשַּׁבָּת, feminine) therefore; for it is holy (קֹדֶשׁ/holiness, masculine) unto you: every one that defileth it shall surely be put to death: for whosoever doeth any work therein, that soul shall be cut off from among his people.”  Leviticus 2:8: “And thou shalt bring the meat offering (אֶת־הַמִּנְחָה, feminine) that is made (אֲשֶׁ֧ר יֵעָשֶׂ֛ה, masculine) of these things unto the Lord: and when it is presented unto the priest, he shall bring it unto the altar.”  Hebrew: כִּֽי־פָקַ֤ד יְהוָה֙ אֶת־חַנָּ֔ה וַתַּ֛הַר וַתֵּ֥לֶד שְׁלֹשָֽׁה־בָנִ֖ים וּשְׁתֵּ֣י בָנ֑וֹת וַיִּגְדַּ֛ל הַנַּ֥עַר שְׁמוּאֵ֖ל עִם־יְהוָֽה׃  Genesis 4:1: “And Adam knew Eve his wife; and she conceived, and bare Cain, and said, I have gotten a man from the Lord (קָנִ֥יתִי אִ֖ישׁ אֶת־יְהוָֽה׃).”