2 Corinthians 10
Now the letter goes into a new section rebuking the false teachers, deceivers, and heretics that had crept into the church at Corinth. Paul also defends his ministry against those who are speaking evil against him.
1 Now I Paul myself beseech you by the meekness and gentleness of Christ, who in presence am base among you, but being absent am bold toward you:
After that first comma it seems like a quote or paraphrase of what some of these false apostles (see 2 Corinthians 11:13-14 when he really exposes them) were saying about Paul. They were basically calling him a coward by claiming he was lowly or humble when he was there but strong and bold when away.
2 But I beseech you, that I may not be bold when I am present with that confidence, wherewith I think to be bold against some, which think of us as if we walked according to the flesh.
Similar to 1 Corinthians 4:21, Paul is advising or beseeching them to handle the matter of these divisive people on their own. These people alleged that Paul and his companions walked after the flesh or according to desires of the flesh. Worldly ambition and so forth.
3 For though we walk in the flesh, we do not war after the flesh:
Though Paul (and us a believers as well) lived in flesh, in the human condition, his warfare was not according to human desires, but heavenly ones, being led by the Spirit.
...every Christian's life is a warfare with Satan, and his principalities and powers, with the world, the men and lusts of it, and with the corruptions of their own hearts; and much more is the life of a minister of the Gospel, who is called forth to meet the adversary in the gate; to stand in the hottest place of the battle, and sustain the whole fire and artillery of the enemy; to fight the good fight of faith, endure hardness as a good soldier of Christ, and with the weapons he is furnished with to war a good warfare: which is not done "after the flesh"; in such a manner as the men of the world wage war with one another; or upon carnal principles; or with carnal selfish views; or in a weak way and manner; but in a spiritual way, with all simplicity and disinterested views, with great courage and intrepidity of mind. -- John Gill
4 (For the weapons of our warfare are not carnal, but mighty through God to the pulling down of strong holds;)
Our weapons are not what the people of the world use (like the false apostles in Corinth using deceit and treachery), but our power is from God and His doctrine. Like Jude 1:9, "...The Lord rebuke thee."
The strong holds we pull down are false doctrines, false philosophy, acceptance of sin in our lives and others etc.
The Christian religion goes forth against all the combined and concentrated powers of resistance of the whole world; and the warfare is to be waged against every strongly fortified place of error and of sin. These strong fortifications of error and of sin are to be battered down and laid in ruins by our spiritual weapons.
-- Albert Barnes
5 Casting down imaginations, and every high thing that exalteth itself against the knowledge of God, and bringing into captivity every thought to the obedience of Christ;
The word for imaginations is "reasonings" or "opinions" and therefore imaginations is an accurate translation. These are all the things people imagine to be so in opposition to the truth of Christianity.
Every high thing or every exalted thing that pretends to be intellectual crumbles before the simple preaching of Christ crucified.
This is Christian warfare. We are not called to tolerate false ideas and just say "to each his own" and go on our merry way.
6 And having in a readiness to revenge all disobedience, when your obedience is fulfilled.
Paul says he's ready to bring justice to those in the church that oppose the truths of Christianity, when the rest of the church is of the same mind.
Adam Clarke has a great comment on this saying, "The apostle was not in haste to pull up the tares, lest he should pull up the wheat also."
7 Do ye look on things after the outward appearance? if any man trust to himself that he is Christ's, let him of himself think this again, that, as he is Christ's, even so are we Christ's.
Don't look at the outward appearance (1 Samuel 16:7).
Basically, if any one (specifically talking about these anti-Paul deceivers in the church) thinks he belongs to Christ, look at what Paul and his fellow workers have done. If this guy is truly in Christ, how much more are those that have been directly commissioned by him (Acts 9:15)? Paul continues to defend his ministry.
8 For though I should boast somewhat more of our authority, which the Lord hath given us for edification, and not for your destruction, I should not be ashamed:
Paul does have a greater authority but it's not to destroy but to edify. If someone is truly in Christ but acting inappropriately we should seek to build them up.
9 That I may not seem as if I would terrify you by letters.
10 For his letters, say they, are weighty and powerful; but his bodily presence is weak, and his speech contemptible.
So Paul has the authority to rebuke these false teachers, but wishes to say no more of it for now and doesn't want to "terrify" them, and those reading this letter.
This might have been someone legit criticisms against Paul but he doesn't want to add fuel to their fire against him. See verse 1.
11 Let such an one think this, that, such as we are in word by letters when we are absent, such will we be also in deed when we are present.
Paul was not a compromiser and would be the same in person as he had been in letters. His words and deeds would match.
12 For we dare not make ourselves of the number, or compare ourselves with some that commend themselves: but they measuring themselves by themselves, and comparing themselves among themselves, are not wise.
We don't want any association or even comparison with those that praise themselves.
Albert Barnes says, "The sense of Paul is, that they [the false apostles] made themselves the standard of excellence; that they were satisfied with their own attainments; and that they overlooked the superior excellence and attainments of others."
13 But we will not boast of things without our measure, but according to the measure of the rule which God hath distributed to us, a measure to reach even unto you.
And here he's building up to verses 17 and 18 showing that if any praise it due to someone, it should all rightfully go to God.
I believe he's talking here and the next couple verses about the grace given him by God to be able to reach Corinth and plant the church there. See 2 Corinthians 3:1-3
14 For we stretch not ourselves beyond our measure, as though we reached not unto you: for we are come as far as to you also in preaching the gospel of Christ:
We don't go beyond what God has called for us to do. Your church and your location is within our range of our missionary work.
15 Not boasting of things without our measure, that is, of other men's labours; but having hope, when your faith is increased, that we shall be enlarged by you according to our rule abundantly,
16 To preach the gospel in the regions beyond you, and not to boast in another man's line of things made ready to our hand.
We speak only of what God has done through us, not taking credit for anyone else's work.
The sense of this is that as Corinth increases in faith and makes the necessary corrections, that Paul and his companions will be able to take care away from Corinth and extend beyond them to other areas. The line, measure, rule, of their work would extend further west.
Remember the numerous problems the church had from 1 Corinthians. This is a church that needed a lot of care!
And this is how churches should be planted. An ordained man is sent to start a church with the help of the home church and is supported until that church can be detached completely.
17 But he that glorieth, let him glory in the Lord.
Speaks for itself (see Jeremiah 9:24). In the next chapter Paul points out that if he would glory according the outward matters he would still outdo the false apostles, but he gives credit to the Lord over everything.
2 Corinthians 11:30, If I must needs glory, I will glory of the things which concern mine infirmities.
18 For not he that commendeth himself is approved, but whom the Lord commendeth.
It is not the guy that brags about himself which is approved of the Lord, but God does the approving.
This chapter and the 11th and 12th do well to be read together.