One of the most common Hebrew synonyms was adultery for idolatry. In the Old Testament these two words are almost always interchangeable. The worship of false gods was described as adultery. The fundamental idea behind this commandment is to have one god. As you read through the Old Testament, you will find that the idea of the adulterous woman who is unfaithful to her husband constantly means the human soul that is turning away to some other god. Emmet Fox