Deuteronomy 18

In chapter 18, Moses reiterates to the people what good worship is, followed by a reminder of what abominable worship practices were. I think for us today, horoscopes and fortune telling, 'karma' and things like that are somewhat close to the divinations and sorcery from that time, in addition to the child sacrifice of the time.

God would talk to them through prophets, and God gives the people a way to verify they are actually speaking from God: "...when a prophet speaks in the name of the LORD, if the word does not come to pass or come true, that is a word that the LORD has not spoken..."