"Who hath made us able ministers of the New Testament, not of the letter, but of the Spirit." The New Testament is the covenant of grace, which was made between the Father and the Son. But, when Christ had performed the conditions of it, and it became sealed and ratified by his blood, and of force by the death of the testator, it then became a testament, valid and of force; and no man may disannul, add thereunto, or make it void. It is of force to every heir of promise, who may come and receive the legacies that are therein appointed by the Father, and bequeathed by the Son, to him.
"An able minister of the New Testament" is one that has received the spirit of promise, one that has felt and enjoyed the truths, blessings, and promises, of the gospel in his own heart, and so "tells to others what God has done for his soul." He has the Spirit, and is a minister of the Spirit; he is a partaker of grace, and a good steward of it; he is pardoned; and preaches, forgiveness; he is justified, and preaches righteousness; he believes, and therefore speaks; he is quickened, and holds forth the word of life; he is free, and preaches liberty to others; he made his own calling and election sure, and therefore shuns not to declare the whole counsel of God. Christ is revealed in him; and he bears him and preaches him amongst the Gentiles. He has felt the savour of his name as an ointment poured forth, and therefore is instrumental in making manifest the savour of his name in every place; he has salt in himself, and his words are seasoned with salt, to season others; he is illuminated, and lets his light shine before men; he is a candle on the stick, and gives, light to all that are in the house. Such an one, in the hands of Christ, is an able minister of the New Testament.
"Not of the letter," which gives no life, no hope, no help; it brings nothing good to the sinner, but calls for everything at his hands; it calls for love, for righteousness, for perfect and perpetual obedience; but gives no grace, mercy, nor salvation. A minister of the letter is a man dead to God, a miscarrying womb, and a dry breast to others; he is an instrument without life, giving uncertain sound; and a well without water, that refreshes none; he may furnish the head, but not manure the heart; he may nurse pride, but never nourish the soul; he may lead to presumption, but never can communicate faith, being but a minister of the letter.
"For the letter killeth." It threatens death temporal to every transgressor. The blasphemer was stoned without the camp; the worshippers of Baal-peor were killed on the spot, he that gathered sticks on the sabbath-day was killed at the command of God; the rebellious child, that dishonoured his parents, was to be stoned. It ministers spiritual death, cursing every transgressor who is under it, and already dead by it; and it ministers eternal death to both body and soul. It condemns the soul to eternal wrath, and the body to endless flames.
"But the Spirit giveth life." It quickens the dead soul, gives it life and feeling, and motion towards God. It removes the sting of death by the application of the atonement, and removes the sentence of death by bringing in the righteousness of Christ. It works faith in the heart, and presents the Lord and giver of life to it, and so enables the soul to live by the faith of the Son of God.