John Flavel was an English Presbyterian preacher who died on 26th June 1691. He was a minister at Dartmouth on the Devon coast. While visiting to preach in Exeter he suddenly died there in his 64th year. He was an effective preacher and a “voluminous and popular author.” In his life time he published over twenty books, and his works are still available in six large volumes.

One of his books was on the text, Proverbs 4:23. Once a man went into a booksellers in London to try to obtain worldly literature. The seller was a Christian and he encouraged the gentleman to purchase Flavel’s latest treatise, “Keeping the Heart.” Inspecting the book, he was not much impressed and said, “What damnable fanatic was he who made this book?” He was promised however, that his money would be returned if he disliked it after a first reading. To this the man agreed. He did read it and was changed! About a month later he returned to the bookshop, not to bring the book back but to order a further one hundred copies for distribution. To the bookseller he said, “I most heartily thank you for putting this book into my hands; I bless God that moved you to do it, it hath saved my soul; blessed be God that ever I came into your shop.”

“Heart-work is hard work indeed. To shuffle over religious duties with a loose and heedless spirit, will cost no great pains; but to set thyself before the Lord, and tie up thy loose and vain thoughts to a constant and serious attendance upon him; this will cost thee something. To attain a facility and dexterity of language in prayer, and put thy meaning into apt and decent expressions, is easy; but to get thy heart broken for sin, while thou art confessing it; melted with free grace while thou art blessing God for it; to be really ashamed and humbled though the apprehensions of God’s infinite holiness, and to keep thy heart in this frame, not only in, but after duty, will surely cost thee some groans and pains of soul. To repress the outward acts of sin, and compose the external part of thy life in a laudable manner, is no great matter; even carnal persons, by the force of common principles, can do this: but to kill the root of corruption within, to set and keep up an holy government over thy thought, to have all things lie straight and orderly in the heart, this is not easy” (John Flavel 1627-1691).