Deuteronomy 12:30

beware that you stumble not after their idols when they shall have been destroyed before you, or lest you seek after their idols, saying, How did these peoples worship their gods, that we may worship as they did?

The word and lest introduces an elliptical construction, as if Scripture had said “and be careful … lest you inquire after their gods, in order to act as they act , saying…”.

in that same manner will I act in worshiping God , thinking that you thereby do well. However, you must not act thus, because all of their actions are abhorrent to God (as evidenced by the subsequent explanation, they even set fire to their sons…). Rather, you must observe that which I have commanded you.

TAKE HEED TO THYSELF THAT THOU BE NOT ENSNARED TO FOLLOW THEM, AFTER THEY ARE DESTROYED FROM BEFORE THEE. “After you see that I destroy them from before you, [you should] pay attention as to why these [nations] were destroyed — because of their corrupt practices. So you too, should not do the same so that others should not come and destroy you.” This is Rashi’s language. And if so, this verse becomes an admonition and warning against idol-worship. And Rashi also wrote on the expression [in the verse before us]: “How did these nations serve their gods, even so will I do likewise. Because Scripture has punished idolatry only for sacrificing, burning incense, pouring a libation, and bowing down, as it is written, [He that sacrificeth unto the gods] save unto the Eternal only, [shall be utterly destroyed, thus establishing the penalty only for those] acts which are performed in the service of G-d, therefore it comes and teaches you here that if the method of worshipping a [particular] idol was something other [than the four ways specified above,] — for example, excreting to [Baal] Peor or throwing a stone to Merkulis, this being its customary manner of worship — he is liable [to the death penalty]. One is also liable for [worshipping any idol whatever, in any one of the four specified ways] sacrificing, burning incense, pouring a libation, and bowing down even if it is not the customary way.” Thus far Rashi’s language. But this is not correct, for the [following] verse states, Thou shalt not do so unto the Eternal thy G-d. If so, the verse [before us] is not an admonition against worshipping their gods, [for it would be incongruous to follow this prohibition with an admonition not to worship G-d] but only that we should not worship the Glorious G-d with their forms of worship, just as he gave the reason, for every abomination to the Eternal, which He hateth, have they done unto their gods etc.
Rather, the meaning of this section is as follows: Up to here he has commanded many times that when we come into the Land we are to uproot the idols and their appurtenances, and destroy their names, and he further commanded that we do this immediately upon dispossessing the nations. Now he stated that when the Eternal will cut off these nations from before us, and the names of the idols will be forgotten in the Land, and we shall dwell in their land securely, we should not think in our hearts thus: “Now G-d has cut …

פן תנקש, as in Psalms 109,11 ינקש נושה, “the creditor will seize,” or as in Daniel 5,6 דא לדא נקשן, “knocked against one another.” (the knees) You are not to move in order to follow them (spiritually).

ואעשה כן גם אני, that I will serve the Lord in Heaven, my G’d, but by imitating the mode of worship practiced by the people whom G’d drove out on my account.