In The Gospel Mystery of Sanctification, The author gives fourteen directions. Then follows his famous sermon on Justification by Faith Alone.
Direction 1: ''the scope of all is to teach you how you may attain to that practice and manner of life which we call holiness, righteousness, or godliness, and which God requires of us.''
Direction 2: ''The holiness which I would bring you to is spiritual (Rom. 7:14). To attain to this grand goal we must know that we are reconciled to God through Christ. If one is to battle with the powers of darkness and the lures of the world, some preparation is needed.
Direction 3: We must fellowship with Christ, and to have this we must be in Christ, and have Christ Himself in us.
Direction 4: We must have faith in Christ, a grace wrought by the Holy Spirit; for it is He who guides us in our quest for a holy life.
Direction 5: We must cast off the belief that true holiness must be attained by sincere works without being new creatures through union with Christ through faith. Gospel holiness is not by works of the law.
Direction 6: The difference between the law and Gospel does not consist in perfect doing, but in believing for life and salvation.
Direction 7: Any change of our hearts and lives from sin to holiness before our receiving of Christ and His salvation by faith is not at all necessary according to the terms of the Gospel, or of the Word.
Direction 8: First we must have justification by faith; we must first live in the Spirit, and then walk in the Spirit.
Direction 9: God gives His new-born babes the comfort of His love and favor, and the hope of happiness, to encourage them to enter into the quest for holiness. The promises also are aimed at this.
Direction 10: Evidently, the comforts of the Gospel necessary for holy practice cannot be received without some assurance of our interest in Christ and His salvation. Means to use to gain assurance.
Direction 11: ''What must we do that we work the works of God.''
''believe on Him whom [God] has sent'' (John 6:28, 29). He puts us first on the work of believing; all else follows in seeking a holy life.
Direction 12: To practice holiness, earnestly pray for God to give the ability to discern the way of holiness, to live by faith, to walk by faith.
Directions 13, 14: More encouragements and means are given.
Gospel sanctification is no dream, but a day by day evidence that the saints go from faith to faith, as they ''grow in grace and in the knowledge of the Lord Jesus Christ'' (2 Pet. 3:18).
Marshall was one of the Puritans that created what is known as ''the golden age of theology.'' He is best known for this book published in 1692.