"Flavel is clear-headed and eloquent in the plain Puritan style, orthodox, Christ-focused and life-centred in his subject-matter, with his mind always set on advancing true godliness, with peace and joy in the Lord."
J. I. Packer, (1926–2020), Rector, All Souls Church, Langham Place, London
""The heart of man is his worst part before it is regenerated, and the best afterward; it is the seat of principles, and the foundation of actions. The eye of the God is, and eye of the Christian ought to be, principally set upon it. The greatest difficulty in conversion is to win the heart to God; and the greatest difficulty after conversation is to keep the heart with God."