The entire book is concerned with the way the true child of God responds to the Gospel, compared to the hypocrite’s response.
An explanation is given of how assurance of salvation relates to the development of spiritual fruits in the believer’s life. It is true that ''By their fruits you shall know them,'' but the believer may know that new life has occurred beforehand. Then there is a comparison of what Shepard calls the ''Gospel hypocrite,'' and the falseness of his confidence. This one must be distinguished from the true child of God The parable, with ease, fits the case of these two groups.
This is the typical Puritan approach to exposition. There must be these ingredients: (1) The Proclamation of what is said; (2) The explanation of the teaching, and, (2) Application of the teaching. Each point must be related to the case of the individual Christian, as well as to the needs of the Church as a redeemed community. All of this is done vigorously, with no sugar-coating to appease shams. The Puritan way is to relate the verses under study to the way the teaching is related to the rest of the Scriptures. Thus it is usual for the actual exposition of the verses in view to be only a small percentage of the total body of truth being taught to the reader.
Through it all is woven the power of the serious anticipation of the second coming of Christ to excite delight in the believer, and yet to disturb the security of the hypocrite. To do this there must be a clear picture of the nature of true repentance, how to recognize the Spirit’s working, and much else of a similar character. One by one the objections which a fleshly heart might make to the overtures of Christ in the Gospel is anticipated, and carefully refuted by the Scriptures. Every intricate twist of the hypocrite’s reasoning is untwisted and laid bare. Each person must ''make their calling and election sure.'' Then they must see the fruits developing in the life.
Shepard is always open-hearted, never morbid, never merely calling forth emotional response, always buttressing every thing he says with copious declarations from the Holy Scriptures.
Thomas Shepard was an early New England Puritan. He preached these 40 sermons from 1636 to 1640, one sermon a week. His work was praised at once by eminent divines, four of them being Westminster Confession participants. Jonathan Edwards quoted this book more than any other.