"As to the subject of these exercises, the author has aimed to blend doctrine, experience, and practice together. There is a danger of antinomianism when the attention is too exclusively called to doctrinal points; of enthusiasm, when it is too exclusively attached to experimental; and of legality, when it is too exclusively confined to practical. It is the proportioned admixture of sentiment, feeling, and duty that qualifies each, and renders them all not only safe, but profitable." -from the preface