Calvin on true worship

'I know how difficult it is to persuade the world that God disapproves of all modes of worship not expressly sanctioned by His Word. The very opposite persuasion which cleaves to them, being seated, as it were in their very bones and marrow, is, that whatever they do has in itself a sufficient sanction, provided it exhibits some kind of zeal for the honour of God.' Tracts & Letters, Vol. 1 THE NECESSITY OF REFORMING THE CHURCH, 129.