Calvin’s Institutes I.xii.1-3
Calvin is at pains to show how the fact that ‘the Lord is one’ (Mk 12:29) is more than just a matter of a name, but extends to his nature. In other words, there is to be no, however subtle, transferring of power or attributes to other beings in our minds. Clearly, Calvin had in his sights the way in which Roman Catholicism viewed Saints. It had got used to the idea that Saints had special powers and to whom application should be made for the benefits of those powers. However, the principle is seen in paganism too. While the concept of the supreme Being remains, effectively attributes of God are thought to be distributed amongst lesser gods.
(What’s the modern secularised equivalent?)
Calvin goes on to note that God as Lawgiver has also defined how right worship should be offered. This is to be expanded upon in later sections.