Notes on the Bible, by Albert Barnes, [1834], at sacred-texts.com
Deuteronomy Chapter 20
Horses, and chariots - The most formidable elements of an Oriental host, which the Canaanites possessed in great numbers; compare Jos 17:16; Jdg 4:3; Sa1 13:5. Israel could not match these with corresponding forces (compare Deu 17:16 note and references), but, having the God of battles on its side, was not to be dismayed by them; the assumption being that the war had the sanction of God, and was consequently just.
The priest - Not the high priest, but one appointed for the purpose, and called, according to the rabbis, "the anointed of the war": hence, perhaps the expression of Jer 6:4, etc. "prepare ye" (literally consecrate) "war." Thus, Phinehas went with the warriors to fight against Midian (Num 31:6; compare Sa1 4:4, Sa1 4:11; Ch2 13:12).
The officers dedicated it - See Exo 5:6 note.
Compare the marginal references. The expression is appropriate, because various ceremonies of a religious kind were customary among the Jews on taking possession of a new house. The immunity conferred in this verse lasted, like that in Deu 20:7 (compare Deu 24:5), for one year.
See the margin and references. The fruit of newly-planted trees was set apart from common uses for four years.
The meaning is that the "officers" should then subdivide the levies, and appoint leaders of the smaller divisions thus constituted.
Directions intended to prevent wanton destruction of life and property in sieges.
Forbearance, however, was not to be shown toward the Canaanite nations, which were to be utterly exterminated (compare Deu 7:1-4). The command did not apply to beasts as well as men (compare Jos 11:11, Jos 11:14).
The parenthesis may he more literally rendered "for man is a tree of the field," i. e., has his life from the tree of the field, is supported in life by it (compare Deu 24:6). The Egyptians seem invariably to have cut down the fruit-trees in war.