“Not that we are sufficient of ourselves to think any thing as of ourselves; but our sufficiency is of God; Who also hath made us able ministers of the new testament; not of the letter, but of the spirit: for the letter killeth, but the spirit giveth life.”

¶ 129 - 130.
An Humble, Earnest and Affectionate Address to the Clergy (1761)
Context: What is the difference between man's own righteousness and man's own light in religion? They are strictly the same thing, do one and the same work, namely, keep up and strengthen every evil, vanity, and corruption of fallen nature. Nothing saves a man from his own righteousness, but that which saves and delivers him from his own light. The Jew that was most of all set against the gospel, and unable to receive it was he that trusted in his own righteousness; this was the rich man, to whom it was as hard to enter into the kingdom of heaven as for a camel to go through the eye of a needle. But the Christian, that trusts in his own light, is the very Jew that trusted in his own righteousness; and all that he gets by the gospel, is only that which the Pharisee got by the Law, namely, to be further from entering into the kingdom of God than publicans and harlots. … Nothing but God in man can be a godly life in man. Hence is that of the apostle, "The letter killeth, but the spirit giveth life." But you will say, can this be true of the spiritual divine letter of the gospel? Can it kill, or give death? Yes, it kills, when it is rested in; when it is taken for divine power, and supposed to have goodness in itself; for then it kills the Spirit of God in man, quenches his holy fire within us, and is set up instead of it. It gives death, when it is built into systems of strife and contention about words, notions, and opinions, and makes the kingdom of God to consist, not in power, but in words. When it is thus used, then of necessity it kills, because it keeps from that which alone is life and can give life. … All the Law, the prophets, and the gospel are fulfilled, when there is in Christ a new creature, having life in and from him, as really as the branch has its life in and from the vine. And when all scripture is thus understood, and all that either Christ says of himself, or his apostles say of him, are all heard, or read, only as one and the same call to come to Christ, in hunger and thirst to be filled and blessed with his divine nature made living within us; then, and then only, the letter kills not, but as a sure guide leads directly to life. But grammar, logic, and criticism knowing nothing of scripture but its words, bring forth nothing but their own wisdom of words, and a religion of wrangle, hatred, and contention, about the meaning of them.
But lamentable as this is, the letter of scripture has been so long the usurped province of school-critics, and learned reasoners making their markets of it, that the difference between literal, notional, and living divine knowledge, is almost quite lost in the Christian world. So that if any awakened souls are here or there found among Christians, who think that more must be known of God, of Christ, and the powers of the world to come, than every scholar can know by reading the letter of scripture, immediately the cry of enthusiasm, whether they be priests, or people, is sent after them. A procedure, which could only have some excuse, if these critics could first prove, that the apostle's text ought to be thus read, "The spirit killeth, but the letter giveth life."