Chapter 12 of Book I of the institutes is relatively brief - and addresses a key component of Calvin's thinking regarding God and honoring Him in worship. He begins by reaffirming our duty to honor God rightly - and in so doing, that we must leave to Him alone the honor befitting His name.
"...he defines lawful worship in order to hold mankind in obedience. He combines both under his law, first when he binds believers to himself to be their sole lawgiver, and then when he prescribes a rule whereby he is to be duly honored according to his own will." (p. 117)God alone has the prerogative and power to declare what worship will be deemed appropriate and which not - and as such, the distinction between worship (latria) that the Roman church claims is appropriate only for God and the worship (dulia) that is allowable and even commanded for the saints and their statues, is a false construct. In practice it is exceedingly hard to understand what the distinction actually is (and using Scriptural examples, Calvin blows out of the water the idea that there is this exclusive distinction by which dead saints may rightly be worshipped). Saints are prayed to, asked to perform tasks, to give what God alone has the prerogative to give. Mary is seen by many as the one through whom God the Father should be approached, because of her kindness and gentle spirit. What wicked perversion this is!
To counter this, Calvin points people to the Scriptures as our only rule, and God's only revelation for the proper rule of worship.
"For by his law it pleases him to prescribe for men what is good and right, and thus to hold them to a sure standard that no one may take leave to contrive any sort of worship he pleases." (p. 120)Calvin will have much more to say on the subject of worship later, but here he lays down a concise consideration. Let GOD bear His rule and make authoritative command of what is and what is not proper worship. Our role is to submit, to trust, and to call upon His name according to His will, which is revealed to us in His word. Inventions of ceremonies is as old as dirt, and has never been acceptable before our Sovereign God. Let us strive for a holy worship that honors Him as He must be honored.