| Gill's Exposition of the Entire Bible And he said unto his lad, run, find out now the arrows which I shoot,.... He no doubt told him the mark which he should shoot at, the stone Ezel, and bid him look out about that for them: and as the lad ran; before he had got to the mark: he shot an arrow beyond him: or it; beyond the lad, or beyond the mark he shot at; purposely shooting with great strength, that he might exceed, and thereby give notice to David how things stood, which was the sign agreed on.
Keil and Delitzsch Biblical Commentary on the Old TestamentTo the latter he said, namely as soon as they had come to the field, Run, get the arrows which I shoot. The boy ran, and he shot off the arrows, "to go out beyond him," i.e., so that the arrows flew farther than the boy had run. The form חצי for חץ only occurs in connection with disjunctive accents; beside the present chapter (1 Samuel 20:36, 1 Samuel 20:37, 1 Samuel 20:38, Chethibh) we find it again in 2 Kings 9:24. The singular is used here with indefinite generality, as the historian did not consider it necessary to mention expressly, after what he had previously written, that Jonathan shot off three arrows one after another.
Geneva Study BibleAnd he said unto his lad, Run, find out now the arrows which I shoot. And as the lad ran, he shot an arrow beyond him.
King James Translators' Notesbeyond...: Heb. to pass over him
Jamieson-Fausset-Brown Bible Commentary36. he said unto his lad, Run, find out now the arrows which I shoot-The direction given aloud to the attendant was the signal preconcerted with David. It implied danger.
Matthew Henry's Concise Commentary20:35-42 The separation of two such faithful friends was grievous to both, but David's case was the more deplorable, for David was leaving all his comforts, even those of God's sanctuary. Christians need not sorrow, as men without hope; but being one with Christ, they are one with each other, and will meet in his presence ere long, to part no more; to meet where all tears shall be wiped from their eyes.
Matthew Henry's Whole Bible CommentaryVerses 35-42 Here is, 1. Jonathan's faithful performance of his promise to give David notice of the success of his dangerous experiment. He went at the time and to the place appointed (v. 35), within sight of which he knew David lay hid, sent his footboy to fetch his arrows, which he would shoot at random (v. 36), and gave David the fatal signal by shooting an arrow beyond the lad (v. 37): Is not the arrow beyond thee? That word [beyond] David knew the meaning of better than the lad. Jonathan dismissed the lad, who knew nothing of the matter, and, finding the coast clear and no danger of a discovery, he presumed upon one minute's personal conversation with David after he had bidden him flee for his life. 2. The most sorrowful parting of these two friends, who, for aught that appears, never came together again but once, and that was by stealth in a wood, ch. 23:16. (1.) David addressed himself to Jonathan with the reverence of a servant rather than the freedom of a friend: He fell on his face to the ground, and bowed himself three times, as one deeply sensible of his obligations to him for the good services he had done him. (2.) They took leave of each other with the greatest affection imaginable, with kisses and tears; they wept on each other's neck till David exceeded, v. 41. The separation of two such faithful friends was equally grievous to them both, but David's case was the more deplorable; for, when Jonathan was returning to his family and friends, David was leaving all his comforts, even those of God's sanctuary, and therefore his grief exceeded Jonathan's, or perhaps it was because his temper was more tender and his passions were stronger. (3.) They referred themselves to the covenant of friendship that was between them, both of them comforting themselves with this in this mournful separation: "We have sworn both of us in the name of the Lord, for ourselves and our heirs, that we and they will be faithful and kind to each other from generation to generation." Thus, while we are at home in the body and absent from the Lord, this is our comfort, that he has made with us an everlasting covenant. | 
