Introduction by J. I. Packer “The heart of man is his worst part before it is regenerated, and the foundation and the best afterward; it is the seat of principles, and the foundation of actions. The eye of 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.” John Flavel (1627-1691) This is John Flavel’s classic work on union and fellowship with God. In a comprehensive and helpful manner Flavel helps us understand better what ‘keeping the heart’ means. He tells us why we should take this commission seriously and speaks about there being particular times when we need to be especially wary of being distracted from our goal. He then shows how we can go on to develop a greater ability in keeping our hearts in tune with God. His advice is timeless, sensitive and profound.