An interesting view of the Scottish Reformer John Knox from Martyn Lloyd Jones in John Knox and the Reformation (Edinburgh: Banner of Truth, 2011), 52-56:
In what sense, then, is it right to say that Knox was ‘the founder of Puritanism’? The first answer is provided by his originality of thought, his independence. The Puritan, by definition, is a man of independence, of independent thought. The Puritan is never ‘an establishment man’. I mean that not only in terms of ‘the establishment of religion’, but in terms of any aspect of establishment. This is, to me, a most important point. There are some people who seem to be born ‘establishment men’. Whatever sphere of life they are in, they are always on the side of the authorities, and of what has always been done, and conditions as they are. Their great concern is to preserve the past. They are found in the Free Churches as commonly as in the Anglican Communion and other forms of Christianity. They are establishment men; and they always start from that position. Now I maintain that the Puritan, by his very nature and spirit, is never an ‘establishment man’ because of his independence and originality, his reading of the Scriptures for himself, and his desire to know the truth irrespective of what others may have said or thought.
Secondly, Knox is ‘the founder of Puritanism’ because he brings out so clearly the guiding principles of Puritanism. That is, first and foremost, the supreme authority of the Scriptures as the Word of God. I need not go into this. Roman Catholicism puts the Church, its tradition and its interpretation of Scripture first; and all imperfectly reformed churches have always continued to do the same. But the peculiar characteristic of the Puritan is that he asserts the supreme authority of the Word of God. This was Knox’s guiding principle. If a thing could not be justified from the Scriptures he would not have it, and he would not allow it to be introduced.
The second guiding principle was that he believed in a ‘root and branch’ reformation. That is not my term; it is his term, and it became the term of others. In other words, the Puritans were not content with a reformation in doctrine only. This is where Knox, and they, disagreed with the leaders in England. All were agreed about the changes in doctrine … but the differentia of Puritanism is that it does not stop at a reformation of doctrine only, but insists that the reformation must be carried through also into the realm of practice. This involves the whole view of the nature of the church. To the Puritan, reformation does not only mean a modification or a slight improvement; it means a ‘new formation’ of the church—not a mere modification of what has already been—governed by the New Testament and its teaching….
Such were his guiding principles. But, and this is most vital in this matter, he applied his principles. There is no such thing, it seems to me, as a theoretical or academic Puritan. There are people who are interested in Puritanism as an idea; but they are traitors to Puritanism unless they apply its teachings; for application is always the characteristic of the true Puritan. It is all very well to extol the ‘Puritan conscience’, but if you do not obey your conscience you are denying Puritanism. Hooper agreed with Knox in so many things, but Hooper had a tendency to go back on what he believed. When Hooper was to be ordained as bishop he said that he would not wear the vestments that were customary, and was sent to gaol; but then, afterwards, he gave in and wore the vestments. The point I am establishing is that the true Puritan not only sees these things, and holds these views, he applies them, he acts on them. This is where Knox is so notable…. He stands out in his conscientious application of what he believed to be the New Testament pattern regarding the nature of the church, and the ordinances and the ceremonies, and the exercise of discipline.