Deuteronomy 21:1

“If one be found slain, etc.] After public war with an enemy, Moses proceeds to speak of a private quarrel and fight of one man with another, in which one is slain, as Aben Ezra observes: in the land which the Lord thy God giveth thee to possess it; where murders might be committed more secretly, and remain undiscovered, when they came to live in separate cities, towns, and villages, with fields adjacent to them, than now encamped together: lying in the field; where the quarrel begun, and where the fight was fought: or, however, where the murderer met with his enemy, and slew him, and left him; it being common for duels to be fought, and murders committed in a field; the first murder in the…”

“EXPIATION OF UNCERTAIN MURDER. (Deu 21:1-9) If one be found slain . . . lying in the field, and it be not known who hath slain him--The ceremonies here ordained to be observed on the discovery of a slaughtered corpse show the ideas of sanctity which the Mosaic law sought to associate with human blood, the horror which murder inspired, as well as the fears that were felt lest God should avenge it on the country at large, and the pollution which the land was supposed to contract from the effusion of innocent, unexpiated blood. According to Jewish writers, the Sanhedrin, taking charge of such a case, sent a deputation to examine the neighborhood. They reported to the nearest town to the spot…”

“The field - Or, in the city, or any place: only the field is named, as the place where such murders are most commonly committed. Deuteronomy 21:2”

“21:1-9 The guilt of murder was usually removed through the death of the murderer (19:11-13; Num 35:30-34). However, if the murderer was unknown, the guilt could still be removed by using this ritual. 21:1 In contrast to the word translated murder in the Ten Commandments (see study note on 5:17), the Hebrew verb here translated murdered (literally pierced through) indicates clear evidence that the death was not by natural causes.”

“Psa 5:6, Psa 9:12; Pro 28:17; Isa 26:21; Act 28:4 Deuteronomy 21:2”

“The reason for grouping together these five laws, which are apparently so different from one another, as well as for attaching them to the previous regulations, is to be found in the desire to bring out distinctly the sacredness of life and of personal rights from every point of view, and impress it upon the covenant nation. Deu 21:1-2 Expiation of a Murder Committed by an Unknown Hand. - Deu 21:1 and Deu 21:2. If any one was found lying in a field in the land of Israel (נפל fallen, then lying, Jdg 3:25; Jdg 4:22), having been put to death without its being known who had killed him (וגו נודע לא, a circumstantial clause, attached without a copula, see Ewald, 341, b. 3), the elders and judges,…”