Knox came upon the scene after the Reformation had been fairly well established in many parts of Europe. The Church of Scotland in his day was more corrupt than the church had been in any other land. It was largely through the energies of Knox that the old church was replaced by a church that featured an open Bible in the language of the people, participation by the congregations equipped with service books and psalm books in their own tongue, the rediscovery of Holy Communion as a corporate action, communion in both kinds (bread and cup), married clergy, the participation of the laity in church affairs, renewed emphasis on the parish, the revival of efficient oversight of clergy and churches, and the elimination of abuses.

As he lay dying he turned to his wife and asked her to read John 17, "where I first cast my spiritual anchor." It is strange that this fiery preacher did not wish to hear from Amos or Hosea, Micah or Jeremiah. This high-priestly prayer of Jesus answered his soul's deep need. According to his biographers he seemed unable to articulate the inner mystical union that he felt with the living Lord.

British ambassador Thomas Randolph said of him: "The voice of this one man is able in one hour to put more life in us than five hundred trumpets blustering in our ears." We know where he got that life. Those who have written most perceptively of him tell us to begin with the inward man, with his prayers. He knew the heights and depths which lay behind the phrase "justification by faith." He said: "I know how hard the battle is. I know the anger, wrath and indignation against God, calling all His promises in doubt, and being ready every hour utterly to fall from God, against which rests only faith."

The man who was famous for having said, "Give me Scotland or I die," had earlier said, "Give me Christ or I cannot live." At his graveside the Regent Morton said: "Here lies one who neither flattered or feared any flesh."

Knox was radical in his religious views and politically opposed to despotism. Such radicalism is often associated with ranting oratory. Knox did not rant. Still, by modern standards, he was inordinately long-winded. Even in his day his sermons must have seemed heavy going. His aim was not so much to inflame his hearers as to argue them into accepting the truth of his messages. Macgregor says:

Listening to Knox was a little like listening to the evidence at a murder trial. At times you wearied of the long drawn-out evidence for a conclusion you might have reached already. But you admired the way he reached it and, above all, the process had all the fascination of a modern detective novel (The Thundering Scot, p. 55).

Sylvstor Home, in his Beecher Lecture, The Romance of Preaching, claims that John Knox "united to the statesmanship of Calvin the fiery eloquence of a Savanarola" (p. 171). Although he was said to have never feared the face of man Knox always spoke of himself as a coward by nature and brave and strong only by grace. He shrank from the ordeal of preaching and entered the pulpit in St. Andrews in 1546 only by the solemn importunity of John Rough, who exhorted him "to refuse not his holy vocation as you look not to avoid God's heavy displeasure."