John Gills Exposition of the Bible Commentary - Deuteronomy 20:18
That they teach you not to do after all their abominations ,.... This is another reason why they were to be utterly destroyed, not only because of the abominations which they committed, but to prevent the Israelites being taught by them to do the same; wherefore, as before observed from Jarchi, such as became proselytes were suffered to live among them, because there was no danger of idolatry from them, which even proselytes of the gate renounced; and though all other abominations are... read more
Matthew Henry's Complete Commentary - Deuteronomy 20:10-20
They are here directed what method to take in dealing with the cities (these only are mentioned, Deut. 20:10; but doubtless the armies in the field, and the nations they had occasion to deal with, are likewise intended) upon which they made war. They must not make a descent upon any of their neighbours till they had first given them fair notice, by a public manifesto, or remonstrance, stating the ground of their quarrel with them. In dealing with the worst of enemies, the laws of justice and... read more