In this letter, John Newton addresses a lady who seems to have been disappointed in some good undertaking. After a brief introduction, he comes to his point:

“One reason why he often disappoints us is, that we may learn to depend on him alone.

While this is not a direct quotation from Scripture, it is a principle which runs through out the Bible. For example, in 2 Corinthians 1, Paul explains that his overwhelming trial had a purpose: “Indeed, we felt that we had received the sentence of death. But that was to make us rely not on ourselves but on God who raises the dead.” 2 Cor. 1:9.

At this point we can err by concluding that all our help from God comes by non-material means; that only a “spiritual” blessing can possibly be of God. Such thinking smacks of gnosticism, and Newton will have none of it. He admits the usefulness of “sensible comforts” but points us to the source of such comforts:

“We are prone, as you observe, to rest too much upon sensible comforts, yet they are very desirable; only, as to the measure and seasons, it is well to be submissive to his will; to be thankful for them when we have them, and humbly waiting for them when we have them not. They are not, however, the proper ground of our hope; a good hope springs from such a sense of our wants, and such a persuasion of his power and grace as engages the heart to venture, upon the warrant of his promises, to trust in him for salvation.

We may use such comforts: when the crowd hungers, Jesus feeds them (John 6:1-14). Yet, we must not trust in such things. Sensible comforts should point us to the one who grants such comforts, not to the comforts themselves (John 6:26).  

A child who receives lunch from his parent should not place his hope in the sandwich, but in his mother who feeds him. The good for the child is relationship with his parent.  In like manner, our good is not the “sensible comfort” God gives us but in the surety of our relationship with God who gives such things. As explained above, God seeks us to seek him (our ultimate good, hope, joy). 
When we realize that the chief end of our existence is to glorify God and enjoy Him forever (Westminster Shorter Catechism, Q. 1), we can understand God’s working:

 “”In a sense, we are often hindering him by our impatience and unbelief; but, strictly speaking, when he really begins the good work, and gives us a desire which will be satisfied with nothing short of himself, he will not be hindered from carrying it on; for he has said, I will work, and none shall let it.”

Newton then anticipates an objection: Must it really be this way? Must my trial have this shape? I once counseled with a man who suffered a grave trial. He said, I could bear trials X, Y and Z (all very painful), but this trial is the one which is too great for me. God, in his wisdom chooses the trial most fit for our soul. 
Now if Newton had said, God has chosen this trial because it is fit for you – it would have easily sounded abusive and uncaring. Therefore, he brings himself into the picture and begins with the proposition: I need such correction:
“”Ah! had it depended upon myself, upon my wisdom or faithfulness, I should have hindered him to purpose, and ruined myself long ago! How often have I grieved and resisted his Spirit! But hereby I have learned more of his patience and tenderness, than I could otherwise have known. He knows our frame, and what effects our evil nature, fomented by the artifices of Satan, will have; he sees us from first to last.”

Note the movement in his argument: He begins with himself and then moves the application to “us”:  “He knows our frame” (an allusion to Psalm 103:14 — you will never be a better counselor, a better pastor, a better Christian than as you know the Scripture).

Newton now comes to the point of correction: but note how the argument moves to Christ. Our trials expose our own weakness: we don’t know if a roof is good until a hard rain. Our trials expose the sin latent in our heart.

“A thousand evils arise in our hearts, a thousand wrongnesses in our conduct, which, as they do arise, are new to ourselves, and perhaps at some times we were ready to think we were incapable of such things; but none of them are new to him, to whom past, present, and future are the same.”

But it is precisely here that Newton displays some pastoral genius (if you will). The exposure of our sin has the tendency to drive the Christian to despair: never one sinned as I! But Newton turns the sin of our sin into a sight of the surpassing love and mercy of God. God knew our sin before we saw it exposed — and yet he loves us:

“The foresight of them did not prevent his calling us by his grace. Though he knew we were vile, and should prove ungrateful and unfaithful, yet he would be found of us; he would knock at the door of our hearts, and gain himself an entrance.  Nor shall they prevent his accomplishing his gracious purpose. It is our part to be abased before him, and quietly to hope and wait for his salvation in the use of his appointed means.”

Having struck, he drives home his point: not only our salvation, but our justification depend upon him. And, to make us know the degree to which we cannot move an inch in our justification without him, our Lord lets us see our sin run wild — like animals–and then brings them to heel (I must say this little bit was a tremendous encouragement to me)

“The power, success, and blessing, are wholly from himself. To make us more sensible of this, he often withdraws from our perceptions: and as, in the absence of the sun, the wild beasts of the forest roam abroad; so, when Jesus hides himself, we presently perceive what is in our hearts, and what a poor shift we can make without him; when he returns, his light chases the evils away, and we are well again. However, they are not dead when most controuled by his presence.”

Before we proceed, consider the profound psychology of Newton’s statement: the animals roaming about are some many things which the psychologist or the psychiatrist would hope to control by drugs or therapy. Here Newton places the problem on a theological basis: those animals can be controlled only by Christ. If the modern Christian Church truly believed this to be so, it would profoundly change the way we consider human beings””

Now Newton pictures the Christian life as a building:

“It is your great and singular mercy, my dear Miss, that he has taught you to seek him so early in life. You are entered in the way of salvation, but you must not expect all at once. The work of grace is compared to the corn, and to a building; the growth of the one, and the carrying forward of the other, are gradual. In a building, for instance, if it be large, there is much to be done in preparing and laying the foundation, before the walls appear above ground; much is doing within, when the work does not seem perhaps to advance without; and when it is considerably forward, yet, being encumbered with scaffolds and rubbish, a by-stander sees it at a great disadvantage, and can form but an imperfect judgment of it.”

At this point, Newton seems to be thinking Paul’s thoughts (1 Cor. 4:4), it is the judgment of God, alone, which matters in the Christian life — and God alone controls the building

“But all this while the architect himself, even from the laying of the first stone, conceives of it according to the plan and design he has formed; he prepares and adjusts the materials, disposing each in its proper time and place, and views it, in idea, as already finished. In due season it is completed, but not in a day. The top-stone is fixed, and then, the scaffolds and rubbish being removed, it appears to others as he intended it should be.”

Newton ends with a doxology — which is the only natural bent of the Christian when considering God. When we consider ourselves — in the light of our indwelling sin & in the light of our savior — we are poor beasts. Yet, when we consider what Savior can and will do, it can only bring praise:

“Men, indeed, often plan what, for want of skill or ability, or from unforeseen disappointments, they are unable to execute: but nothing can disappoint the heavenly Builder; nor will he ever be reproached with forsaking the work of his own hands, or beginning that which he could not or would not accomplish; Phil. 1:6. Let us therefore be thankful for beginnings, and patiently wait the event. His enemies strive to retard the work, as they did when the Jews, by his order, set about rebuilding the Temple: yet it was finished, in defiance of them all.”