In the preceding verses the apostle Paul spoke very plainly in defence of his ministry, having stated that God always caused him and his fellow ministers to triumph in Christ, that they were a sweet fragrance of Christ unto God and to their hearers and that they did not corrupt the Word of God (as some did) but preached faithfully the gospel of God's grace and mercy in Christ.
(Vs. 1.) "Are we bragging about ourselves? Are we guilty of vain glory? Are we seeking to commend ourselves, or are we recommending ourselves to you and seeking letters of recommendation from you to others? Some preachers may feel the need of credentials and letters of recommendation from place to place, but we do not need them."
(Vs. 2.) "You are our credentials; you are our letters of recommendation." Paul was God's messenger to them and the instrument God used to bring them to a knowledge of Christ (Rom. 10:13-15; 2 Cor. 5:20,21). Their embracing the gospel of Christ, their faith, holiness and love and their perseverance in grace were testimonials to all men that God was with Paul and that God had sent him. They were written in his heart, not statistics and glowing reports on paper!
(Vs. 3.) He told them in the previous verse that they were his epistles written on his heart and did more to recommend him than all the reports on paper. But he is careful to ascribe to the Lord Jesus all the glory, for he says here that they are really the epistles of Christ! Paul is only the instrument the Lord used to preach to them. It was Christ, who, by his Spirit, wrote his law on their hearts, shed abroad his love in their hearts and saved them by his grace (Rom. 5:5-9; Eph. 2:8-10). The law of Christ is written not on tables of stone, as at Sinai, but on the heart of the believer (Ezek. 36:26, 27; Jer. 31:33).
(Vs. 4.) "This is the hope, trust and confidence that we have through Christ toward, and with reverence to God. God has saved and called us to preach, through our ministry has called you to faith and has given us all access to his throne of grace the person and work of Christ, our Lord. This is our hope and confidence (Col. 1:12-23; 2:9, 10).
(Vs. 5.) Although Paul strongly defended his call to preach and declared that the Corinthians were proof and the fruits of his ministry, he would not leave the impression that he ascribed anything to himself, to any power or sufficiency in himself. He says that we are not sufficient even to think (which is the lowest human act) anything truly and spiritually good, much less sufficient for so great a work as the conversion of a soul. "Our power, ability and sufficiency are of God. His grace is sufficient to enable us to repent, believe, embrace Christ and preach, and to enable you to receive our gospel (2 Cor. 5:18, 19). God did not find us sufficient, but he made us sufficient. The best preacher of the gospel is no more than what the grace of God makes him (1 Cor. 15:10).
(Vs. 6.) "God has made us, or qualified us, to be ministers of the new covenant, or the covenant of grace, of which Jesus Christ is the Mediator and Surety." In the following verses the apostle makes a comparison between the old covenant and the new, the law of Moses and the free grace and gospel of Christ (Heb. 8:6; 12:24; 13:20). The covenant of grace is called "the new covenant", not because it is newly made (for it is the everlasting covenant) nor even because it is newly revealed (for it is revealed in prophecy, promise and types throughout the Old Testament) but because it is now fulfilled in the person and work of Christ, it is now manifested clearly in the gospel message (Rom. 3:21, 22), and it is forever new, it will never give way to another covenant (Heb. 10:9,10). "We are ministers, not of the letter of the law" (Rom. 7:6), which shows what is to be done, thought and said and what is not to be done, without giving any ability to obey its commands and with no power to sanctify or justify those who are under it (Rom. 3:19, 20), "but we are ministers of the gospel which, in the hands of the Holy Spirit, gives spiritual life, and eternal life." The bare letter of the law kills, in that it reveals sin, inability and enmity (Rom. 7:7-10; Gal. 3:10). The gospel of Christ is the Spirit who gives life, quickening dead sinners, working true repentance toward God and faith in Christ, writing the commandments of God on the heart and mind, and who actually justifies, sanctifies and makes the believer a new creature in Christ (2 Cor. 5:17; Gal. 5:22). We must be careful not to minister the gospel in letter and doctrine only, but in demonstration of the Spirit and power (1 Cor. 2:1-5).