In Deuteronomy 12 it seems that Moses begins his second or third speech, depending how we outline the book. The ESV Study Bible calls this the second speech and says it runs from Deuteronomy 12:1-26:19. Remember that Deuteronomy is a series of sermons, or speeches, which Moses delivers to the people before they enter the promised land. Deuteronomy 12 is about proper worship and the end of the chapter is a warning against idolatry.