Verse 12: And he sent, and brought him in. Now he was (1 Sam. 17:42; Song 5:10) ruddy, and withal of a beautiful countenance (Heb. fair of eyes), and goodly to look to. (so 1 Sam. 9:17) And the LORD said, Arise, anoint him: for this is he.
[He was ruddy (thus nearly all interpreters)] Red (Montanus); reddish, for I think that it is to be referred to his hair, not his cheeks (Piscator).
He was ruddy; which may be referred either to the colour of his hair; or rather, to the complexion of his face.
[And fair in appearance, עִם־יְפֵ֥ה עֵינַ֖יִם] With beauty (brightness [Pagnine, Junius and Tremellius]) of eyes (Septuagint, similarly Jonathan, Syriac, Arabic, Montanus). Beyond this, that he was having shining and attractive eyes, he was of a fair appearance and handsome countenance (Vatablus). עִם/with here is in the place of ו/and (Hebrews in Vatablus, Glassius). Verbatim: with beautiful to the eyes; that is, and beautiful to the eyes. Thus 1 Samuel 17:42. Certain interpreters: with beauty. But in the Hebrew it is not abstract (which is written יְפִי, Ezekiel 28:7, or יֳפִי, Zechariah 9:17), but concrete, יְפֵה, which is the construct form of יָפֶה/beautiful. So also in Genesis 39:6, יְפֵה is put in the construct state. Thus in Nahum 3:12, all thy strong holds (shall be like) fig trees, עִם/and the first fruits (Glassius’ “Grammar” 587). Moreover, a beautiful soul is wont also to appear in the countenance. See Plato’s Symposium (Grotius). The form in David was not weakened or soft, but manly and martial. His eyes appeared to emanate a certain bellicose ferocity (Martyr).
Goodly to look to; of a comely but masculine and majestic aspect.
[And in a handsome countenance, וְט֣וֹב רֹ֑אִי] And handsome in appearance (Vatablus). The noun רֹאִי/sight/appearance here is of the same form as חֺלִי/ infirmity (Munster).
[circa 1065 BC] Verse 13: Then Samuel took the horn of oil, and (1 Sam. 10:1; Ps. 89:20) anointed him in the midst of his brethren: and (see Num. 27:18; Judg. 11:29; 13:25; 14:6; 1 Sam. 10:6, 10) the Spirit of the LORD came upon David from that day forward. So Samuel rose up, and went to Ramah.
[And he anointed him in the midst of his brethren] Question: Did his brothers understand the matter? Response 1: Some answer in the negative (thus Menochius, Sanchez, Martyr). It is certain that his brothers witnessed the anointing; it is not so certain that they understood what that anointing meant (Sanchez). Perhaps, when afterwards they were hearing that David sings and prophesies, they were thinking that he was made a Prophet by that anointing (Martyr, similarly Cajetan in Sanchez). Others suppose that Samuel indicated nothing concerning the kingdom, but only said this, that God chose one of the sons of Jesse to conduct some great business; and that not even David himself (nor Jesse [Cajetan in Sanchez]) understood that he was going to be king (Martyr). It is evident that Samuel took precautions that these things might be done with the greatest secrecy. But if his brothers had known it, it would easily have become known among the common people, from the jealousy, or rejoicing, of his brothers; and do neither Samuel, nor David and his family, would have escaped the fury of Saul. Also, it was not well agreeing with that royal inauguration that he was immediately returned to his pastoral labors (Sanchez). Neither would his brothers have so freely chided him (Sanchez, Martyr); unless perchance they had despised this, and had held it as sport (Martyr). Response 2: Others answer in the affirmative. He was anointed, while nevertheless previously Samuel had explained to him, and to his father and brethren standing round, the will of God. See 2 Samuel 5:2 (Malvenda and Piscator out of Junius, similarly Lapide, Serarius, Tostatus in Lapide, Sà in Menochius): so that his brothers might thereafter think more highly of him, and labor under less jealousy, since they saw him preferred before them (Theodoret in Lapide). David was anointed before witnesses. For, Samuel was going to die before David was publicly inaugurated. And so it was necessary that that deed be confirmed by the testimony of Jesse, his father, and by the conscience of David himself (Martyr). For it is likely that he revealed the mystery to David and Jesse (Menochius). Moreover, this anointing did not give the Kingdom to David, but destined him for the Kingdom; and it gave to him the right of preserving himself, by whatever means he could, until the time of the taking of the Kingdom (Grotius). At that time David received the right of rule unto the people, but not yet in the people. Just as the Lawyers say that a son, while his father lives, has a right unto the goods, but not in the goods (Fagius). He was anointed, not so that he might reign immediately; so that he might succeed Saul in the kingdom upon Saul’s death (Lapide). See how innocently David is called to the kingdom. He makes use of no ambition, no grasping, as one altogether ignorant of what would be done (Martyr).
In the midst of his brethren: according to this translation, his brethren were present at this act, and knew that David was anointed king. But this seems, to some, neither consistent with Samuel’s design of secrecy, nor with Eliab’s scornful words concerning him after this, 1 Samuel 17:28. But to this others reply, that David’s brethren saw David’s unction, but did not particularly understand that he was anointed to the kingdom; but were only told by Samuel that he was anointed to some great service, which hereafter they should know, but at present it was fit to be concealed. Thus Jesse only and David understood the whole business, and his brethren were able to attest to that act of Samuel’s anointing him, which, with other collateral evidences, was abundantly sufficient to prove David’s right to the kingdom, if need should be. And this seems fairly to accord and explain the matter. But the words may be otherwise translated out of the Hebrew, that he anointed him out of the midst of his brethren, that is, he selected him from amongst the rest of his brethren to be king; as Christ is said to be raised from the midst of his brethren. And whereas the Hebrew word is בְּקֶרֶב/bekereb, in the midst, not מִקֶּרֶב/ mikkereb, out of the midst; it is confessed that the preposition ב/beth, in, is oft used for מִן/min, of, or out of, as hath been formerly showed by many instances; and so it may be here. And further, the place may be thus rendered, that Samuel anointed him, being taken out of the midst of his brethren; and so these words may be added, to signify that Samuel took him out from the rest of the company, and privately anointed him; Jesse only being present at the action. And thus there is an ellipsis of a verb or particle, which is frequent; as Genesis 12:15, The woman was taken (that is, was taken and carried) into Pharaoh’s house; and many such places.
[And the Spirit of the Lord was directed to David from that day, and thereafter, וַתִּצְלַ֤ח רֽוּחַ־יְהוָה֙ אֶל־דָּוִ֔ד מֵהַיּ֥וֹם הַה֖וּא וָמָ֑עְלָה] And the Spirit of Jehovah caused to succeed (or, remained [Pagnine, similarly Jonathan in Munster], rested [Vatablus]) upon David from that day, and beyond (Montanus, Septuagint, Jonathan), or, and thereafter (Pagnine). He entered, or pervaded, him (Munster out of Kimchi). Others: He began to stir him up (certain interpreters in Munster). He invaded David, that is, with grat force and efficacy. Concerning this term see more things on 1 Samuel 10:6; Judges 14:6 (Malvenda). And the Spirit of the Lord, rushing upon David, moved him from that day, and thereafter (Junius). Hebrew: and upwards. It is Catachresis: The name of a place to signify a time (Piscator). Moreover, this Spirit did not pass through, but remained constantly upon David (Lapide, similarly Martyr out of the Chaldean). The Spirit of the Lord here is the spirit of fortitude, prophecy, and prudence (Vatablus, Lapide, Sanchez, Martyr, Tirinus). After this anointing David began to psalm, and dared to assail the lion and the bear (Tirinus out of Sanchez).
The Spirit of the Lord came upon David from that day forward, that is, he was immediately endowed with extraordinary gifts of God’s Spirit, as strength, and courage, and wisdom, and magnanimity, and other excellent qualities, which fitted him for and put him upon noble attempts; for which he presently grew famous, even whilst he lived a private life. See below, 1 Samuel 16:18; 17:34, etc.
[And Samuel, arising, departed to Ramah] Leaving the outcome of the matter to God, and not applying any external force to obtain the kingdom (Martyr).
 Hebrew: וַיִּשְׁלַ֤ח וַיְבִיאֵ֙הוּ֙ וְה֣וּא אַדְמוֹנִ֔י עִם־יְפֵ֥ה עֵינַ֖יִם וְט֣וֹב רֹ֑אִי פ וַיֹּ֧אמֶר יְהוָ֛ה ק֥וּם מְשָׁחֵ֖הוּ כִּֽי־זֶ֥ה הֽוּא׃  Hebrew: עִם־יְפֵ֥ה עֵינַ֖יִם.  Hebrew: וְה֣וּא אַדְמוֹנִ֔י.  1 Samuel 17:42: “And when the Philistine looked about, and saw David, he disdained him: for he was but a youth, and ruddy, and of a fair countenanceוְאַדְמֹנִ֖י) עִם־יְפֵ֥ה מַרְאֶֽה׃, with beautiful of sight).”  Ezekiel 28:7: “Behold, therefore I will bring strangers upon thee, the terrible of the nations: and they shall draw their swords against the beauty (יְפִי) of thy wisdom, and they shall defile thy brightness.”  Zechariah 9:17: “For how great is his goodness, and how great is his beauty (יָפְיוֹ)! corn shall make the young men cheerful, and new wine the maids.”  Genesis 39:6: “And he left all that he had in Joseph’s hand; and he knew not ought he had, save the bread which he did eat. And Joseph was a goodly person, and well favoured (יְפֵה־תֹ֖אַר וִיפֵ֥ה מַרְאֶֽה׃).”  Nahum 3:12: “All thy strong holds shall be like fig trees with the firstripe figs (כָּ֙ל־מִבְצָרַ֔יִךְ תְּאֵנִ֖ים עִם־בִּכּוּרִ֑ים): if they be shaken, they shall even fall into the mouth of the eater.” רֹאִי/sight/appearance is related to the verb רָאָה, to see; חֺלִי/infirmity, to חָלָה, to be weak or sick.  Hebrew: וַיִּקַּ֙ח שְׁמוּאֵ֜ל אֶת־קֶ֣רֶן הַשֶּׁ֗מֶן וַיִּמְשַׁ֣ח אֹתוֹ֮ בְּקֶ֣רֶב אֶחָיו֒ וַתִּצְלַ֤ח רֽוּחַ־יְהוָה֙ אֶל־דָּוִ֔ד מֵהַיּ֥וֹם הַה֖וּא וָמָ֑עְלָה וַיָּ֣קָם שְׁמוּאֵ֔ל וַיֵּ֖לֶךְ הָרָמָֽתָה׃  Hebrew: וַיִּמְשַׁ֣ח אֹתוֹ֮ בְּקֶ֣רֶב אֶחָיו֒.  Thomas Cajetan (1469-1534) was an Italian Dominican. He was a theologian of great repute, and a learned proponent of a modified Thomism (Neo-Thomism). Due to his considerable talents, he was made a cardinal. Cajetan proved to be one of the more able opponents of the Reformation. He commented on much of the Old Testament, including the historical books (Joshua-Esther).  Emanuel Sa (1530-1596) was a Portuguese Jesuit. He distinguished himself as a teacher of Philosophy at Coimbra, and was called to Rome as Professor of Divinity. Pope Paul V assigned him the responsibility of supervising the production of a new edition of the Vulgate. His Notationes in Totam Scripturam Sacram are brief, but learned and judicious.  Theodoret (393-457) was bishop of Cyrus, and a significant participant in the Christological controversies of his age. He was an advocate of Antiochian dyophysitism, or moderate Nestorianism, although he condemned the Nestorian affirmation of two Sons in Christ, and the Nestorian denial that Mary was Theotokos, that is, the Mother of God. His orthodoxy was cleared at the Council of Chalcedon (451). With respect to exegetical method, Theodoret came up under the tutelage of Theodore of Mopsuestia and John Chrysostom. He commented on most of the books of the Bible; his comments on the Scripture are sober, and clear in expression.  Paul Fagius (1504-1550) was among the early Reformers and a Hebrew scholar of some ability. He studied in Germany and labored there, first as a schoolmaster, then as a minister. Feeling pressure from the rising tide of the Counter-Reformation, he left Germany for England in 1549, and died at Cambridge in 1550. His bones were later burned during the reign of Queen Mary. Fagius wrote Translationum Præcipuarum Veteris Testamenti inter Se Variantium Collatio. צָלַח signifies to rush, or to prosper.  David Kimchi (c. 1160-1235) was a famous Spanish Rabbi. He wrote a commentary on the entire Old Testament and a Hebrew grammar, as a result of which he has long been respected for his profound scholarship.  1 Samuel 10:6: “And the Spirit of the Lord will come upon thee (וְצָלְחָ֤ה עָלֶ֙יךָ֙ ר֣וּחַ יְהוָ֔ה), and thou shalt prophesy with them, and shalt be turned into another man.”  Judges 14:6: “And the Spirit of the Lord came mightily upon himוַתִּצְלַ֙ח עָלָ֜יו ר֣וּחַ) יְהוָ֗ה), and he rent him as he would have rent a kid, and he had nothing in his hand: but he told not his father or his mother what he had done.”  That is, an improper use of the word.  1 Samuel 17:34, 36, 37.