Marshall’s book, published in 1692 (12 years after his death), sets out 14 directions on the doctrine of sanctification and its relationship to justification. It is publication with an introduction by Joel Beeke, published by Reformation Heritage Books.
Direction I: That we may acceptably perform the duties of holiness and righteousness required by the law, our first work is to learn the powerful and effectual means whereby we may attain to so great an end.
Marshall begins with the proposition that Christians are required to holiness: we are saved to holiness The question is how, what is the means by which we attain to such holiness?
He notes that if we take seriously the doctrine of original sin, we must recognize that we in ourselves lack the ability to attain to such holiness. And he rebukes those who merely insist upon holiness as if it merely required effort and self-will:
Yea, many that are accounted powerful preachers, spend all their zeal in the earnest pressing the immediate practice of the law, without any discovery [disclosure] of the effectual means of performance: as if the works of righteousness were like those servile employments that need no skill and artifice at all, but industry and activity.
The means for sanctification is a grace communicated by God to us — it cannot be known without God’s disclosure. The means appointed by God are the Scriptures received by faith: “God hath given, in the holy scriptures by his inspiration, plentiful instruction in righteousness, that we may be thoroughly furnished for every good work….[W]e cannot apply ourselves ourselves to the practice of holiness, with hope of success, except we have some faith concerning divine assistance, which we have no ground to expect, if we use not such means as God has appointed to work by.”