Formerly titled "A Faithful Admonition to the Professors of God's Truth in England," this letter is said to be "undoubtedly the most important" of Knox's writings (up to that time) by W. Stanford Reid in Trumpeter of God (p. 114).

Furthermore Reid notes that Knox's, "[v]iews on the magistrate expressed in the 'Faithful Admonition,' were to have an important influence upon much of his future conduct, and upon the development of the Reformation in both England and Scotland."

The editor of Knox's Works states, "[t]he object of the Admonition was twofold. The one was to animate those who had made a good profession to perseverance, and to avoid the sin of apostatizing, or appearing to conform to the 'abominable idolatry' re-established in England; the other, to point out the dangers to be apprehended in when the kingdom became subjected to the dominion of strangers."

Knox uses very strong language here, in the hopes of getting through to those who came to be termed Nicodemites (i.e. those who thought that they could, in Knox's words, "keep faith secretly in the heart, and yet do as idolaters do," -- for more on the Nicodmeites see Carlos Erie's War Against the Idols: The Reformation of Worship from Erasmus to Calvin).

Written at a time when the true church had been driven underground by Roman Catholic persecution, it was said concerning this letter that "many other godly men besides have been exposed to the risk of their property, and even life itself, upon the sole ground of either having had this book in their possession, or having read it."

Kevin Reed gives an excellent summary of this letter in Selected Writings of John Knox, when, in part, he writes, "[w]hile acknowledging the risk of persecution to the faithful, the reformer perceives a greater danger in compromising with idolatry. Government persecution may bring disfavour of men, loss of personal goods and, in some cases, physical death; but idolatry brings down the wrath of God, resulting in grievous punishments, now and through eternity. Idolatry also invites a curse upon the posterity of the nation. In an intense pastoral appeal, Knox strongly admonishes his readers to avoid conforming to the Romish rites of worship" (p. 220)

For those who would rather read many of Knox's writings (including this title) with contemporary spelling, punctuation, and grammar we highly recommend the Selected Writings of John Knox.