Ye shall perish quickly from off the good land - The following note from Mr. John Trapp is very judicious: "This judgment Joshua inculcates Jos 23:13, Jos 23:15, and here, because he knew it would be a very grievous thing to them to forego so goodly a land, so lately gotten, and so short a while enjoyed. In the beginning of a speech τα ηθη, the milder affections, suit best; but towards the end τα παθη, passionate and piercing passages; according to the orator. This rule Joshua observes, being Ex utroque Caesar; no less an orator than a warrior."
In all this exhortation we see how closely Joshua copies the example of his great master Moses. See Lev 26:7, Lev 26:8, Lev 26:14, etc.; Deu 28:7; Deu 32:30. He was tenderly concerned for the welfare of the people, and with a deeply affected heart he spoke to their hearts. No people ever were more fairly and fully warned, and no people profited less by it. The threatenings pronounced here were accomplished in the Babylonish captivity, but more fully in their general dispersion since the crucifixion of our Lord. And should not every Christian fear when he reads, If God spared not the natural branches, take heed that he spare not thee? Surely a worldly, carnal, and godless Christian has no more reason to expect indulgence from the justice of God than a profligate Jew. We have a goodly land, but the justice of God can decree a captivity from it, or a state of bondage in it. The privileges that are abused are thereby forfeited. And this is as applicable to the individual as to the whole system.

When ye have transgressed the covenant of the Lord your God,

which he commanded you,.... The law, so called, and the several precepts of it, particularly those which relate to the faith and worship of the one only true God; see Exo 24:7;

and have gone and served other gods, and have bowed down yourselves unto them; been guilty of idolatry, of having and worshipping other gods, which are no gods, with or besides the God of Israel, see Jos 23:7,

then shall the anger of the Lord be kindled against you; nothing being more provoking to him than idolatry, he being a jealous God of his honour and worship:

and ye shall perish quickly from off the good land which he hath given unto you; as they did at the time of the Babylonish captivity, and at the last destruction of Jerusalem by the Romans.

Next: Joshua Chapter 24

BY THREATENINGS IN CASE OF DISOBEDIENCE. (Jos 23:12)

Else if ye do in any wise go back, and cleave unto the remnant of these nations--As marriage connections with the idolatrous Canaanites would present many and strong temptations to transgress it, these were strictly prohibited (Exo 34:12-16; Deu 7:3). With his eye, as it were, upon those prohibitions, Joshua threatens them with the certain withdrawal of the divine aid in the further expulsion of the Canaanites (a threat founded Exo 23:33; Num 33:55; Deu 7:16).

Next: Joshua Chapter 24