Some Moravian scholars point to a different formula as a guide to constructive debate about faith. This formula was first advanced by Luke of Prague (1460–1528), one of the bishops of the ancient Unitas Fratrum. Luke taught that one must distinguish between things that are essential, ministerial or incidental to salvation. The essentials are God's work of creation, redemption and sanctification, as well as the response of the believer through faith, hope and love. Things ministerial are such items as the Bible, church, sacraments, doctrine and priesthood. These mediate the sacred and should thus be treated with respect, but they are not considered essential. Finally, incidentals include things such as vestments or names of services that may reasonably vary from place to place