John Knox’s discourse is set amidst the struggles of the Scottish Reformation. Knox contends that all religious ceremonies and institutions must have clear biblical warrant, if they are to be admitted as valid expressions of worship – a concept which has subsequently become known as the regulative principle of worship.
This work was originally produced in 1550, under the title of A Vindication of the Doctrine that the Sacrifice of the Mass is Idolatry. Knox delivers some potent blows against the Mass and he bases his arguments upon scriptural proof that all worship invented by man, or which lacks biblical warrant, is idolatry. Thus, the entire discussion turns upon Knox’s defense of the scriptural law of worship.