Deuteronomy 20:18

18 lest peradventure they teach you to do all the abominations, which they have wrought (un)to their gods, and ye do sin against your Lord God (and then ye sin against the Lord your God).

Deuteronomy 20:18 Meaning and Commentary

Deuteronomy 20:18

That they teach you not to do after all their abominations,
&c.] 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 included, yet this is particularly respected, as appears from the following clause:

which they have done unto their gods;
to the honour of whom not only many superstitious rites and ceremonies were performed, and idolatrous actions committed, but acts of lewdness, and even unnatural uncleanness:

so should ye sin against the Lord your God;
a sin the most provoking to him, as the sin of idolatry was; and cause his anger to rise to such a degree, as to suffer them to be carried captive from the land he gave them to inherit; and which afterwards, was the case, and that through learning the manners and customs of these people; see ( Psalms 106:34-42 ) .

Deuteronomy 20:18 In-Context

16 But of these cities that shall be given to thee, thou shalt not suffer any to live, but thou shalt slay by the sharpness of sword; (But in these cities that shall be given to thee by the Lord, thou shalt not allow anyone to remain alive, but thou shalt kill them all by the sharpness of the sword;)

17 that is to say, Hittites, and Amorites, and Canaanites, and Perizzites, and Hivites, and Jebusites, as thy Lord God hath commanded to thee;

18 lest peradventure they teach you to do all the abominations, which they have wrought (un)to their gods, and ye do sin against your Lord God (and then ye sin against the Lord your God).

19 When thou hast besieged a city by long time, and thou hast compassed it with strongholds that thou overcome it, thou shalt not cut down the trees, of which men may eat/of which fruit may be eaten, neither thou shalt waste the country(side) about with axes; for it is a tree, and not a man, neither it may increase the number of fighters against thee. (When thou hast besieged a city for a long time, and thou hast surrounded it with strongholds so that thou can overcome it, thou shalt not cut down the trees, from which men can eat/whose fruit can be eaten, nor shalt thou destroy all the countryside about with axes; for it is a tree, and not a man, and it cannot increase the number of fighters against thee.)

20 And if any of them be not apple trees, but be wild, and able into other uses, cut them down, and make of them engines, till thou take the city that fighteth against thee. (But if any of them be not apple trees, or other kinds of fruit trees, but be wild, and good for other uses, then cut them down, and make engines, or bulwarks, out of them, until thou take the city that fighteth against thee.)