Archibald Alexander, in Thoughts Concerning Religious Experience (1844):“Why is there so little advancement made [in living the Christian life]? First, there is a defect in our belief in the freeness of divine grace. To exercise unshaken confidence in the doctrine of gratuitous pardon is one of the most difficult things in the world… Christians cannot but be lean and feeble when deprived of their proper nourishment. It is by faith that the spiritual life is made to grow; and the doctrine of free grace, without any mixture of human merit, is the only true object of [that] faith. Until preachers inculcate clearly, fully and practically, the grace of God manifested in the gospel, we shall have no vigorous growth… among professing Christians.” Using an anology based on this helpful quote, I suppose we could say that the doctrine of free grace is the Miracle Grow of the soul.