Do we begin again to commend ourselves - By speaking thus of our sincerity, Divine mission, etc., is it with a design to conciliate your esteem, or ingratiate ourselves in your affections? By no means.

Or need we - epistles of commendation - Are we so destitute of ministerial abilities and Divine influence that we need, in order to be received in different Churches, to have letters of recommendation? Certainly not. God causes us to triumph through Christ in every place; and your conversion is such an evident seal to our ministry as leaves no doubt that God is with us.

Letters of commendation - Were frequent in the primitive Church; and were also in use in the apostolic Church, as we learn from this place. But these were, in all probability, not used by the apostles; their helpers, successors, and those who had not the miraculous gifts of the Spirit, needed such letters and they were necessary to prevent the Churches from being imposed on by false teachers. But when apostles came, they brought their own testimonials, the miraculous gifts of the Holy Spirit.

begin.

2 Corinthians 2:17 For we are not as many, which corrupt the word of God: but as of sincerity, but as of God, in the sight of God speak we in Christ.

2 Corinthians 5:12 For we commend not ourselves again to you, but give you occasion to glory on our behalf...

2 Corinthians 10:8,12 For though I should boast somewhat more of our authority, which the Lord has given us for edification, and not for your destruction...

2 Corinthians 12:11,19 I am become a fool in glorying; you have compelled me: for I ought to have been commended of you...

1 Corinthians 3:10 According to the grace of God which is given to me, as a wise master builder, I have laid the foundation, and another builds thereon...

1 Corinthians 4:15 For though you have ten thousand instructors in Christ, yet have you not many fathers...

1 Corinthians 10:33 Even as I please all men in all things, not seeking my own profit, but the profit of many, that they may be saved.

epistles.

Acts 18:27 And when he was disposed to pass into Achaia, the brothers wrote, exhorting the disciples to receive him: who, when he was come...

1 Corinthians 16:3 And when I come, whomsoever you shall approve by your letters, them will I send to bring your liberality to Jerusalem.

The Letter and the Spirit
(Twelfth Sunday after Trinity.) II COR. iii. 6. God, who 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. When we look at the Collect, Epistle, and Gospel for to-day one after the other, we do not see, perhaps, what they have to do with each other. But they have to do with each other. They agree with each other. They explain each other. They all three tell us what God is like, and what we are to believe …
Charles Kingsley—The Good News of God

Note F. Note from Bengel on Rom. I. 4.
According to the Spirit of Holiness. The word hagios, holy, when God is spoken of, not only denotes the blameless rectitude in action, but the very Godhead, or to speak more properly, the divinity, or excellence of the Divine nature. Hence hagiosune (the word here used) has a kind of middle sense between hagiotes, holiness, and hagiasmos, sanctification. Comp. Heb. xii. 10 (hagiotes or holiness), v. 14 (hagiasmos or sanctification). So that there are, as it were, three degrees: sanctification, …
Andrew Murray—Holy in Christ

The Authority and Utility of the Scriptures
2 Tim. iii. 16.--"All scripture is given by inspiration of God, and is profitable for doctrine, for reproof, for correction, for instruction in righteousness." We told you that there was nothing more necessary to know than what our end is, and what the way is that leads to that end. We see the most part of men walking at random,--running an uncertain race,--because they do not propose unto themselves a certain scope to aim at, and whither to direct their whole course. According to men's particular …
Hugh Binning—The Works of the Rev. Hugh Binning