This passage is a typical OT sandwich pattern where one key truth is sandwiched between two others. The are all important, but the one in the middle is central and key. In this case, the central idea is verse 13 - “Pay attention to all that I have said to you, and make no mention of the names of other gods, nor let it be heard on your lips." In short, it means worship God alone, without exception! A recurring theme all through the Covenant, and a restatement of the very first commandments in the 10 Words.
