In a classic sermon on Romans 9 and the hardening of Pharaoh’s heart, Jonathan Edwards said this:

‎‎‎When God is here spoken of as hardening some of the children of men, it is not to be understood that God by any positive efficiency hardens any man’s heart. There is no positive act in God, as though he put forth any power to harden the heart. To suppose any such thing would be to make God the immediate author of sin. God is said to harden men in two ways: by withholding the powerful influences of his Spirit, without which their hearts will remain hardened, and grow harder and harder; in this sense he hardens them, as he leaves them to hardness. And again, by ordering those things in his providence which, through the abuse of their corruption, become the occasion of their hardening.

from Jonathan Edwards' sermon God's Sovereignty in the Salvation of Men

From his sermon Safety, Fullness, and Sweet Refreshment, to be Found in Christ, Jonathan Edwards comments on the excellency of Christ in light of Isaiah 55:1-2;

The excellency of Christ is such, that the discovery of it is exceedingly contenting and satisfying to the soul. The inquiry of the soul is after that which is most excellent. The carnal soul imagines that earthly things are excellent; one thinks riches most excellent, another has the highest esteem of honour, and to another carnal pleasure appears the most excellent; but the soul cannot find contentment in any of these things, because it soon finds an end to their excellency.

Worldly men imagine, that there is true excellency and true happiness in those things which they are pursuing. They think that if they could but obtain them, they should be happy; and when they obtain them, and cannot find happiness, they look for happiness in something else, and are still upon the pursuit.

But Christ Jesus has true excellency, and so great excellency, that when they come to see it they look no further, but the mind rests there. It sees a transcendent glory and an ineffable sweetness in him; it sees that till now it has been pursuing shadows, but that now it has found the substance; that before it had been seeking happiness in the stream, but that now it has found the ocean. The excellency of Christ is an object adequate to the natural cravings of the soul, and is sufficient to fill the capacity. It is an infinite excellency, such an one as the mind desires, in which it can find no bounds; and the more the mind is used to it, the more excellent it appears. Every new discovery makes this beauty appear more ravishing, and the mind sees no end; here is room enough for the mind to go deeper and deeper, and never come to the bottom. The soul is exceedingly ravished when it first looks on this beauty, and it is never weary of it. The mind never has any satiety, but Christ’s excellency is always fresh and new, and tends as much to delight, after it has been seen a thousand or ten thousand years, as when it was seen the first moment. The excellency of Christ is an object suited to the superior faculties of man, it is suited to entertain the faculty of reason and understanding, and there is nothing so worthy about which the understanding can be employed as this excellency; no other object is so great, noble, and exalted.

This excellency of Jesus Christ is the suitable food of the rational soul. The soul that comes to Christ, feeds upon this, and lives upon it; it is that bread which came down from heaven, of which he that eats shall not die; it is angels’ food, it is that wine and milk that is given without money, and without price. This is that fatness in which the believing soul delights itself; here the longing soul may be satisfied, and the hungry soul may be filled with goodness. The delight and contentment that is to be found here, passeth understanding, and is unspeakable and full of glory. It is impossible for those who have tasted of this fountain, and know the sweetness of it, ever to forsake it. The soul has found the river of water of life, and it desires no other drink; it has found the tree of life, and it desires no other fruit.

In one of his most popular works, The Life and Diary of David Brainerd, Jonathan Edwards gives an account of what David Brainerd said on his deathbed:

My heaven is to please God, and glorify him, and to give all to him, and to be wholly devoted to his glory: that is the heaven I long for; that is my religion, and that is my happiness, and always was ever since I suppose I had any true religion: and all those that are of that religion shall meet me in heaven.—I do not go to heaven to be advanced, but to give honour to God. It is no matter where I shall be stationed in heaven, whether I have a high or low seat there; but to love, and please, and glorify God is all. Had I a thousand souls, if they were worth any thing, I would give them all to God; but I have nothing to give, when all is done.

David Brainerd (1718-1747) was an early American missionary to the American Indians. His work was a major driving force and inspiration to the domestic and foreign missionary movement of the late eighteenth and through the nineteenth century. Christians all over the world continue to be inspired by his life of self-denial, his sincere and strenuous labor on behalf of others, and his devotion to prayer.

Edwards discusses the necessity of evil in order to fully display God’s glory:

It is a proper and excellent thing for infinite glory to shine forth; and for the same reason, it is proper that the shining forth of God’s glory should be complete; that is, that all parts of his glory should shine forth, that every beauty should be proportionably effulgent, that the beholder may have a proper notion of God. It is not proper that one glory should be exceedingly manifested, and another not at all; for then the effulgence would not answer the reality. For the same reason it is not proper that one should be manifested exceedingly, and another but very little. It is highly proper that the effulgent glory of God should answer his real excellency; that the splendour should be answerable to the real and essential glory, for the same reason that it is proper and excellent for God to glorify himself at all.

Thus it is necessary, that God’s awful majesty, his authority and dreadful greatness, justice, and holiness, should be manifested. But this could not be, unless sin and punishment had been decreed; so that the shining forth of God’s glory would be very imperfect, both because these parts of divine glory would not shine forth as the others do, and also the glory of his goodness, love, and holiness would be faint without them; nay, they could scarcely shine forth at all.

If it were not right that God should decree and permit and punish sin, there could be no manifestation of God’s holiness in hatred of sin, or in showing any preference, in his providence, of godliness before it. There would be no manifestation of God’s grace or true goodness, if there was no sin to be pardoned, no misery to be saved from. How much happiness soever he bestowed, his goodness would not be so much prized and admired, and the sense of it not so great, as we have elsewhere shown. We little consider how much the sense of good is heightened by the sense of evil, both moral and natural.

And as it is necessary that there should be evil, because the display of the glory of God could not but be imperfect and incomplete without it, so evil is necessary, in order to the highest happiness of the creature, and the completeness of that communication of God, for which he made the world; because the creature’s happiness consists in the knowledge of God, and sense of his love. And if the knowledge of him be imperfect, the happiness of the creature must be proportionably imperfect; and the happiness of the creature would be imperfect upon another account also; for, as we have said, the sense of good is comparatively dull and flat, without the knowledge of evil.

The Works of Jonathan Edwards: Remarks on Important Theological Controversies (Chapter 3: Concerning the Divine Decrees in General, and Election in Particular), Originally published in 1834.