For these nations. As God had just before been setting before them the punishment He was about to inflict upon these nations, in order to alarm and warn them, so now does he admonish them that the inheritance was handed over to them on this condition, that they should be mindful of so great a benefit, and beware of all pollutions; and that they succeeded the former inhabitants of the land, with a view to their being separate from them; for whence was this change, except that God might acquire to Himself a new people, and purify the land from all its defilements? Although He only mentions two classes of superstitions, yet thus, by synecdoche, He indicates them all. The sum is, that they should not be like the nations in vices and corruptions, which had been the cause of their destruction; since God had not only exterminated the men themselves, but their abominable rites also. Some divide the latter part of the verse into two clauses, "but thou shalt not do so;" and then, "Jehovah gives you the land," which last word they supply. But I do not hesitate to think that the pronoun 'th, athah, must be thus rendered, "But as for thee;" and then I think it must be read continuously, "God hath not suffered thee to do so," for the word ntn, nathan, is of extensive signification. The tendency of the whole is, that the prohibition of God should be of more weight with them than the example of the nations.

For those nations which thou shall possess hearkened unto observers of times, and unto diviners,.... Such as are before mentioned, and did as they directed them:
but as for thee, the Lord thy God hath not suffered thee so to do; or, "but thou not so" (m) thou shouldest not do so, not hearken to such persons, but to the Lord thy God, and to his law and testimony; nor art thou left to the deception of such persons:
the Lord thy God hath given thee: his word and statutes, as a rule to go by, which he has not given to other nations: the Targum of Jonathan adds,"the priests shall ask by Urim and Thummim, and a true prophet shall the Lord your God give unto you;''so that they had no need to hearken to such impostors and deceivers: or, "as for thee, not so are they whom the Lord thy God giveth thee" (n); that is, the prophets whom the Lord would give unto them would not be like the diviners of the Heathens, who imposed on the people and deceived them; but would be men sent and inspired by God, and true and faithful in the discharge of their office; and to hearken to these they are encouraged by the promise of a very eminent one, like to Moses, in the next verse.
(m) "et tu non sic", Montanus. (n) "De teau tem non ita sunt quos dat tibi Jehova Deus tuus", Junius & Tremellius.

Hath not suffered thee so to do - Hath not suffered thee to follow these superstitious and diabolical practices, as he hath suffered other nations to do, but hath instructed thee better by his word and spirit, and will more fully instruct thee by a great prophet.