The interpretation timeline
1 Samuel 16:6 Douay-Rheims

And when they were come in, he saw Eliab, and said: Is the Lord’s anointed before him?

A.D. 215 – 1871 8 witnesses

Patristic

before A.D. 750
215
A.D.
c. A.D. 150–215
“They have gone beyond the limits of impropriety. They have invented mirrors to reflect all this artificial beautification of theirs, as if it were nobility of character or self-improvement. They should, rather, conceal such deception with a veil. It did the handsome Narcissus no good to gaze on his own image, as the Greek myth tells us. If Moses forbade his people to fashion any image to take the place of God, is it right for these women to study their reflected images for no other reason that to distort the natural features of their faces?In much the same way, when Samuel the prophet was sent to anoint one of the sons of Jesse as king, and when he brought out his chrism as soon as he saw the oldest son, admiring his handsomeness and height, Scripture tells us, "The Lord said to him: 'Look not on his countenance, nor on the height of his stature, because I have rejected him. For man sees those things that appear, but the Lord beholds the heart.' " He finally anointed not the one who was fair in body but the one who was fair of soul. If the Lord places more importance on beauty of soul than on that of the body, what must he think of artificial beautification when he abhors so thoroughly every sort of lie? "We walk by faith, not by sight."”
Source
220
A.D.
Tertullian Patristic
c. A.D. 150–220
“You are human, and so you know other people only from the outside. You think as you see, and you see only what your eyes let you see. But "the eyes of the Lord are lofty." "Man looks on the outward appearance, God looks on the heart." So "the Lord knows them that are his" and roots up the plant which he has not planted. He shows the last to be first, he carries a fan in his hand to purge his floor. Let the chaff of light faith fly away as it pleases before every wind of temptation. So much the purer is the heap of wheat which the Lord will gather into his garner.”
Source
389
A.D.
A.D. 329–390
“Do not say, "I do not mind a mere priest, if he is a celibate, and a religious [person], and of angelic life; for it would be a sad thing for me to be defiled even in the moment of my cleansing." Do not ask for credentials of the preacher or the baptizer. For another is his judge and the examiner of what you can't see. For humans look on the outward appearance, but the Lord looks on the heart.”
Source

Scholastic

c. 1100 – 1500
1105
A.D.
Rashi Jewish
1040–1105
“He said, "Surely, before Adonoy is His annointed." He said to himself, 'Surely, it is true that this one is fitting for the kingship.'”

Post-Reformation

c. 1650 – 1900
1714
A.D.
Matthew Henry Reformed
1662–1714
“If the sons of Jesse were told that God would provide himself a king among them (as he had said, Sa1 16:1), we may well suppose they all made the best appearance they could, and each hoped he should be the man; but here we are told, I. How all the elder sons, who stood fairest for the preferment, were passed by. 1. Eliab, the eldest, was privately presented first to Samuel, probably none being present but Jesse only, and Samuel thought he must needs be the man: Surely this is the Lord's anointed, Sa1 16:6. The prophets themselves, when they spoke from under the divine direction, were as liable to mistake as other men; as Nathan, Sa2 7:3. But God rectified the prophet's mistake by a secret whisper to his mind: Look not on his countenance, Sa1 16:7. It was strange that Samuel, who had been so wretchedly disappointed in Saul, whose countenance and stature recommended him as much as any man's could, should be so forward to judge of a man by that rule. When God would please the people with a king he chose a comely man; but, when he would have one after his own heart, he should not be chosen by the outside. Men judge by the sight of the eyes, but God does not, Isa 11:3. The Lord looks on the heart, that is, (1.) He knows it. We can tell how men look, but he can tell what they are. Man looks on the eyes (so the original word is), and is pleased with the liveliness and sprightliness that appear in them; but God looks on the heart, and sees the thoughts and intents of that. (2.) He judges of men by it. The good disposition of the heart, the holiness or goodness of that, recommends us to God, and is in his sight of great price (Pe1 3:4), not the majesty of the look, or the strength and stature of the body. Let us reckon that to be true beauty which is within, and judge of men, as far as we are capable, by their minds, not their mien. 2. When Eliab was set aside, Abinadab and Shammah, and, after them, four more of the sons of Jesse, seven in all, were presented to Samuel, as likely for his purpose; but Samuel, who not attended more carefully than he did at first to the divine direction, rejected them all: The Lord has not chosen these, Sa1 16:8, Sa1 16:10. Men dispose of their honours and estates to their sons according to their seniority of age and priority of birth, but God does not. The elder shall serve the younger. Had it been left to Samuel, or Jesse, to make the choice, one of these would certainly have been chosen; but God will magnify his sovereignty in passing by some that were most promising as well as in fastening on others that were less so. II. How David at length was pitched upon. He was the youngest of all the sons of Jesse; his name signifies beloved, for he was a type of the beloved Son. Observe, 1. How he was in the fields, keeping the sheep (Sa1 16:11), and was left there, though there was a sacrifice and a feast at his father's house. The youngest are commonly the fondlings of the family, but, it should seem, David was least set by of all the sons of Jesse; either they did not discern or did not duly value the excellent spirit he was of. Many a great genius lies buried in obscurity and contempt; and God often exalts those whom men despise and gives abundant honour to that part which lacked. The Son of David was he whom men despised, the stone which the builders refused, and yet he has a name above every name. David was taken from following ewes to feed Jacob (Psa 78:71), as Moses from keeping the flock of Jethro, an instance of his humility and industry, both which God delights to put honour upon. We should think a military life, but God saw a pastoral life (which gives advantage for contemplation and communion with heaven), the best preparative for kingly power, at least for those graces of the Spirit which are necessary to the due discharge of that trust which attends it. David was keeping sheep, though it was a time of sacrifice; for there is mercy that takes precedence of sacrifice. 2. How earnest Samuel was to have him sent for: "We will not sit down to meat" (perhaps it was not the feast upon the sacrifice, but a common meal) "till he come hither; for, if all the rest be rejected, this must be he." He that designed not to sit at table at all is now waited for as the principal guest. If God will exalt those of low degree, who can hinder? 3. What appearance he made when he did come. No notice is taken of his clothing. No doubt that was according to his employment, mean and coarse, as shepherds' coats commonly are, and he did not change his clothes as Joseph did (Gen 41:14), but he had a very honest look, not stately, as Saul's, but sweet and lovely: He was ruddy, of a beautiful countenance, and goodly to look to (Sa1 16:12), that is, he had a clear complexion, a good eye, and a lovely face; the features were extraordinary, and there was something in his looks that was very charming. Though he was so far from using any art to help his beauty that his employment exposed it to the sun and wind, yet nature kept its own, and, by the sweetness of his aspect, gave manifest indications of an amiable temper and disposition of mind. Perhaps his modest blush, when he was brought before Samuel, and received by him with surprising respect, made him look much the handsomer. 4. The anointing of him. The Lord told Samuel in his ear (as he had done, Sa1 9:15) that this was he whom he must anoint, Sa1 16:12. Samuel objects not the meanness of his education, his youth, or the little respect he had in his own family, but, in obedience to the divine command, took his horn of oil and anointed him (Sa1 16:13), signifying thereby, (1.) A divine designation to the government, after the death of Saul, of which hereby he gave him a full assurance. Not that he was at present invested with the royal power, but it was entailed upon him, to come to him in due time. (2.) A divine communication of gifts and graces, to fit him for the government, and make him a type of him who was to be the Messiah, the anointed One, who received the Spirit, not by measure, but without measure. He is said to be anointed in the midst of his brethren, who yet, possibly, did not understand it as a designation to the government, and therefore did not envy David (as Joseph's brethren did him), because they saw no further marks of dignity put upon him, no, not so much as a coat of divers colours. But bishop Patrick reads it, He anointed him from the midst of his brethren, that is, he singled him out from the rest, and privately anointed him, but with a charge to keep his own counsel, and not to let his own brethren know it, as by what we find (Sa1 17:28), it should seem, Eliab did not. It is computed that David now was about twenty years old; if so, his troubles by Saul lasted ten years, for he was thirty years old when Saul died. Dr. Lightfoot reckons that he was about twenty-five, and that his troubles lasted but five years. 5. The happy effects of this anointing: The Spirit of the Lord came upon David from that day forward, Sa1 16:13. The anointing of him was not an empty ceremony, but a divine power went along with that instituted sign, and he found himself inwardly advanced in wisdom, and courage, and concern for the public, with all the qualifications of a prince, though not at all advanced in his outward circumstances. This would abundantly satisfy him that his election was of God. The best evidence of our being predestinated to the kingdom of glory is our being sealed with the Spirit of promise, and our experience of a work of grace in our own hearts. Some think that his courage, by which he slew the lion and the bear, and his extraordinary skill in music, were the effects and evidences of the Spirit's coming upon him. However, this made him the sweet psalmist of Israel, Sa2 23:1. Samuel, having done this, went to Ramah in safety, and we never read of him again but once (Sa1 19:18), till we read of his death; now he retired to die in peace, since his eyes had seen the salvation, even the sceptre brought into the tribe of Judah.”
1771
A.D.
John Gill Reformed
1697–1771
“And it came to pass, when they were come,.... Jesse and his sons, into the house where the entertainment was; and perhaps before they sat down, went into a private apartment by the direction of Samuel, where he acquainted Jesse with the business he came upon: that he looked on Eliab; who was Jesse's firstborn, Ch1 2:13, called Elihu, Ch1 27:18. and said, surely the Lord's anointed is before him; or this is the person it is his pleasure should be anointed king.”
Source
1849
A.D.
1774–1849
“Him. Hebrew, “surely the Lord’s anointed is in his presence.” This he spoke by his own spirit, judging from the comeliness of Eliab. (Calmet) — But the beauty of Saul’s body had concealed a deformed soul. (Haydock)”
1871
A.D.
1871
“Samuel said, Surely the Lord's anointed is before him--Here Samuel, in consequence of taking his impressions from the external appearance, falls into the same error as formerly (Sa1 10:24).”
Modern · 1953 →

The in-app commentary runs from the Fathers to the early-modern record, then stops — that's where the public-domain sources end, not where the reading does. For the modern reading, follow the sources directly.