John Gills Exposition of the Bible Commentary - Deuteronomy 21:1
If one be found slain ,.... 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... read more
Matthew Henry's Complete Commentary - Deuteronomy 21:1-9
Care had been taken by some preceding laws for the vigorous and effectual persecution of a wilful murderer (Deut. 19:11-13), the putting of whom to death was the putting away of the guilt of blood from the land; but if this could not be done, the murderer not being discovered, they must not think that the land was in no danger of contracting any pollution because it was not through any neglect of theirs that the murderer was unpunished; no, a great solemnity is here provided for the putting... read more