12:30. Beware lest thou imitate them, after they are destroyed at thy coming in, and lest thou seek after their ceremonies, saying: As these nations have worshipped their gods, so will I also worship.
12:31. Thou shalt not do in like manner to the Lord thy God. For they have done to their gods all the abominations which the Lord abhorreth, offering their sons and daughters, and burning them with fire.
12:32. What I command thee, that only do thou to the Lord: neither add any thing, nor diminish.
That only do thou, etc… They are forbid here to follow the ceremonies of the heathens; or to make any alterations in the divine ordinances.
Deuteronomy Chapter 13
False prophets must be slain, and idolatrous cities destroyed.
13:1. If there rise in the midst of thee a prophet or one that saith he hath dreamed a dream, and he foretell a sign and a wonder,
13:2. And that come to pass which he spoke, and he say to thee: Let us go and follow strange gods, which thou knowest not, and let us serve them:
13:3. Thou shalt not hear the words of that prophet or dreamer: for the Lord your God trieth you, that it may appear whether you love him with all your heart, and with all your soul, or not.
13:4. Follow the Lord your God, and fear him, and keep his commandments, and hear his voice: him you shall serve, and to him you shall cleave.