In Letter IX in the collection entitled “Forty-One Letters”, John Newton answers the question from a young man concerning the doctrines of grace. What is most interesting in the letter is not Newton’s explication of the doctrines of grace per se, but rather his instruction on how to read the Bible.

First, Newton explains that we do not really understand anything if we can merely recite a creed or have a notional understanding of some theological propositions. For instance, I may know about the nature of the worship of a god by ancient Israelites, but I don’t really understand what those Israelites thought and felt in their worship — I can understand the outside, but I can’t feel and see what they felt and saw.

This truth is even more so when it comes to the knowledge of the true God. There is a level of apprehension which goes beyond mere emotional experience. As Newton writes:

We may become wise in notions, and so far masters of a system, or scheme of doctrine, as to be able to argue, object, and fight, in favour of our own hypothesis, by dint of application, and natural abilities; but we rightly understand what we say, and whereof we affirm, no farther than we have a spiritual perception of it wrought in our hearts by the power of the Holy Ghost. It is not, therefore, by noisy disputation, but by humble waiting upon God in prayer, and a careful perusal of his holy word, that we are to expect a satisfactory, experimental, and efficacious knowledge of the truth as it is in Jesus. I

John Newton, Richard Cecil, The Works of the John Newton, vol. 1 (London: Hamilton, Adams & Co., 1824), 188.

He then proceeds to list four guidelines for understanding the Scripture.

First, in handling difficult text or seeming obscure passages, rely upon the “analogy of faith”:

 there is a certain comprehensive view of scriptural truth, which opens hard places, solves objections, and happily reconciles, illustrates, and harmonizes many texts, which to those who have not this master-key, frequently styled the analogy of faith, appear little less than contradictory to each other. When you obtain this key, you will be sure that you have the right sense.

Here is a brief note on the analogy of faith:

Analogia fidei is a concept that has many advocates but few who carefully define it. Henri Blocher has carefully marked out four distinct meanings for the concept of the analogy of faith: 1) the traditional one as set forth by Georg Sohnius (c. 1585):3 “the apostle prescribes that interpretation be analogous to faith (Rom 12:6), that is, that it should agree with the first axioms or principles, so to speak, of faith, as well as with the whole body of heavenly doctrine”; 2) the “perspicuity” of Scripture definition, as championed by Martin Luther, in which the sense of the text is to be drawn from the clear verses in the Bible and thus issue in the topically selective type of analogia fidei; 3) the thematically selective understanding of the analogy of faith, as defended by John Calvin: “When Saint Paul decided that all prophecy should conform to the analogy and similitude of faith (Rom 12:6), he set a most certain rule to test every interpretation of Scripture”;4 and 4) the view held by the majority of Protestants, which may be described as a more formal definition, the analogia totius Scripturae. In this view all relevant Scriptures on any topic are brought to bear in order to establish a position that coheres with the whole of the Bible. The analogy of faith on this view is the harmony of all biblical statements where the text is expounded by a comparison of similar texts with dissimilar ones.

Walter C. Kaiser, Jr., Hermeneutics And The Theological Task Trinity Journal 12, no. 1 (1991): 2-4

Second, Newton cautions that one’s reading must be understood in light of real life “consult with experience.” Here is an example of how Newton applied this principle in his writing to the young man in this letter:

But we are assured that the broad road, which is thronged with the greatest multitudes, leads to destruction. Were not you and I in this road? Were we better than those who continue in it still? What has made us differ from our former selves? Grace. What has made us differ from those who are now as we once were? Grace. Then this grace, by the very terms, must be differencing, or distinguishing grace; that is, in other words, electing grace

Third, do not be prejudiced against the truth on the ground that it does not align with your current theological position. I recall R. C. Sproul saying that if John MacArthur were convinced of some truth from Scripture, and if that truth contradicted a position MacArthur held, that MacArthur would instantly change his mind. We need to be willing to allow the truth overrule our position.  Although offered in a very different context and for a different purpose, Emerson’s famous line has some applicability here, “A foolish consistent is the hobgoblin of little minds”.  We should never be stubborn against the truth.

Finally, Newton explains that we should favor those readings which make much of God and God’s glory:

This is an excellent rule, if we can fairly apply it. Whatever is from God, has a sure tendency to ascribe glory to him, to exclude boasting from the creature, to promote the love and practice of holiness, and increase our dependence upon his grace and faithfulness. The Calvinists have no reason to be afraid of resting the merits of their cause upon this issue; notwithstanding the unjust misrepresentations which have been often made of their principles, and the ungenerous treatment of those who would charge the miscarriages of a few individuals, as the necessary consequence of embracing those principles.

John Newton, Richard Cecil, The Works of the John Newton, vol. 1 (London: Hamilton, Adams & Co., 1824), 189–190.