Why did Thomas Boston (d. 1732) strongly endorse “The Marrow of Modern Divinity” and write study notes for it? Because he wanted Christians to understand the biblical and practical aspects of the law/gospel distinction. Here’s Boston in his own words:
That which I aim at, and intend therein, is to show unto myself, and others that shall read it [The Marrow], the difference betwixt the Law and the Gospel, a point, as I conceive, very needful for us to be well instructed in, and that for these reasons:
First, Because, if we be ignorant thereof, we shall be very apt to mix and mingle them together, and so to confound the one with the other; which, as Luther on the Galatians, p. 31, truly says, “doth more mischief than man’s reason can conceive;” and therefore he doth advise all Christians, in the case of justification, to separate the Law and the Gospel as far asunder as heaven and earth are separated.
Secondly, Because if we know right how to distinguish betwixt them, the knowledge thereof will afford ns no small light towards the true understanding of the Scripture, and will help us to reconcile all such places, both in the Old and New Testament, as seem to be repugnant; yea, and it will help us to judge aright of cases of conscience, and quiet our own conscience in time of trouble and distress; yea, and we shall thereby be enabled to try the truth and falsehood of all doctrines….Thomas Boston, The Whole Works of Thomas Boston: An Explication of the Assembly’s Shorter Catechism, ed. Samuel M‘Millan, vol. 7 (Aberdeen: George and Robert King, 1850), 459.
Indeed, the law/gospel distinction is not only biblical and helpful for understanding Scripture rightly, it is also very practical for Christian living!
Covenant Presbyterian Church (OPC)
Hammond, WI, 54015