Knox speaks of having been in “the puddle of papistry.”  He loathes what he has left behind him, and it is natural to guess that, in his first years of priesthood, his religious nature slept; that he became a priest and notary merely that he “might eat a morsel of bread”; and that real “conviction” never was his till his studies of Protestant controversialists, and also of St. Augustine and the Bible, and the teaching of Wishart, raised him from a mundane life.  Then he awoke to a passionate horror and hatred of his old routine of “mumbled masses,” of “rites of human invention,” whereof he had never known the poetry and the mystic charm.  Had he known them, he could not have so denied and detested them.  On the other hand, when once he had embraced the new ideas, Knox’s faith in them, or in his own form of them, was firm as the round world, made so fast that it cannot be moved.  He had now a pou sto, whence he could, and did, move the world of human affairs.  A faith not to be shaken, and enormous energy were the essential attributes of the Reformer.  It is almost impossible to find an instance in which Knox allows that he may have been mistaken:  d’avoir toujours raison was his claim.  If he admits an error in details, it is usually an error of insufficient severity.  He did not attack Northumberland or Mary Stuart with adequate violence; he did not disapprove enough of our prayer book; he did not hand a heretic over to the magistrates.

While acting as a priest and notary, between 1540, at latest, and 1543, Knox was engaged as private tutor to a boy named Brounefield, son of Brounefield of Greenlaw, and to other lads, spoken of as his “bairns.”  In this profession of tutor he continued till 1547.

Knox’s personal aspect did not give signs of the uncommon strength which his unceasing labours demanded, but, like many men of energy, he had a perpetual youth of character and vigour.  After his death, Peter Young described him as he appeared in his later years.  He was somewhat below the “just” standard of height; his limbs were well and elegantly shaped; his shoulders broad, his fingers rather long, his head small, his hair black, his face somewhat swarthy, and not unpleasant to behold.  There was a certain geniality in a countenance serious and stern, with a natural dignity and air of command; his eyebrows, when he was in anger, were expressive.  His forehead was rather narrow, depressed above the eyebrows; his cheeks were full and ruddy, so that the eyes seemed to retreat into their hollows:  they were dark grey, keen, and lively.  The face was long, the nose also; the mouth was large, the upper lip being the thicker.  The beard was long, rather thick and black, with a few grey hairs in his later years. {12} The nearest approach to an authentic portrait of Knox is a woodcut, engraved after a sketch from memory by Peter Young, and after another sketch of the same kind by an artist in Edinburgh.  Compared with the peevish face of Calvin, also in Beza’s Icones, Knox looks a broad-minded and genial character.