“obedience is the foundation of true worship”

“If we desire, therefore, that he should approve of the honor which we confer upon him, we ought always to consider what he requires. And, indeed, they who venture to offer to God honors invented by themselves are chargeable with using some sort of force and violence towards him; for obedience is the foundation of true worship. Let us also learn from it with what reverence we ought to abide by the pure and simple word of God; for as soon as we turn aside in the smallest degree, the truth is poisoned by our leaven, so that it is no longer like itself.”

John Calvin, Commentary on John 6:15