John Knox (c. 1514–1572) was a pivotal Scottish theologian and minister who led the Protestant Reformation in Scotland, instrumental in establishing the Presbyterian Church and the Reformed confessional tradition. He was a courageous preacher who emphasized the authority of Scripture and the sovereignty of God, famously laboring to ensure that the Kirk was reformed according to the regulative principle and biblical order.
John Knox was the central human figure in the Scottish Reformation, serving as a preacher and architect of the Church of Scotland. His ministry was characterized by a resolute commitment to the notes of the true Church, which he identified as the preaching of the Word, the right administration of the sacraments, and the upright exercise of ecclesiastical discipline, as noted in the Scots Confession — Chapter XVIII. He stood against the abuses of the Roman hierarchy, consistently pointing the Church back to the teaching of the prophets and apostles.
Like his contemporary John Calvin, Knox believed that the only hope for the Church was the grace of God revealed in Jesus Christ. The Scots Confession — Chapter XVI reflects the theology that Knox championed: that the Church is the body and spouse of Christ, and that outside of this communion in Christ, there is no salvation. Knox's preaching was not merely social reform, but an urgent call for the nation to embrace the Doctrines of Grace and to worship the Triune God in spirit and in truth, rejecting all idolatry.