‘For though we walk in the flesh, we do not war according to the flesh, for the weapons of our warfare are not of the flesh, but mighty before God to the casting down of strongholds, casting down imaginations, and every high thing that is exalted against the knowledge of God, and bringing every thought into captivity to the obedience of Christ.'
This is Paul's reply. It is a play on what his opponents are saying. Yes, he says, we do walk in human bodies, but it is not with those, or with fleshly aims and methods, that we fight the spiritual warfare. ‘We do not war according to the flesh.' We do not fight as men do, or use fleshly weapons, or with fleshly purposes in mind. Our aims and our weapons are spiritual. Thus weapons like intimidation, manipulation, half truths, trickery, being double-tongued, and using hypocritical behaviour, all things of which Paul had been accused, are ineffective in spiritual warfare
For, he says, the weapons of their warfare are not of the flesh, ‘but are mighty through God to the destroying of strongholds.' Compare Proverbs 21:22 LXX, ‘A wise man assaults strong cities, and demolishes the fortress in which the ungodly trusted.' God has through His Spirit given them mighty power against all strongholds, both of men and of Satan (compare Zechariah 4:6-7). The stronghold was the strongpoint within a city that could continue to hold out even when the city had fallen. It was the last to fall and its fall indicated total victory. And there are many strongholds that have to be brought crashing down. The strongholds of men's imaginations and (false) reasonings. The strongholds of men's exalted opinions of themselves, and of their exaltation of themselves. The strongholds of high thoughts which are not really high thoughts at all, which claim superior knowledge of Christ but are not really in obedience to Christ, which claim special illumination by the Spirit, but are not of the Spirit at all. These he will bring down.
‘Casting down imaginations, and every high thing that is exalted against the knowledge of God, and bringing every thought into captivity to the obedience of Christ.' Indeed the Spirit working through them breaks down men's imaginations and arguments, He breaks down men's pride and arrogance, He breaks down men's refusal to face the truth of the knowledge of God, and breaks down the blinding force of Satan that blinds their minds to it (2 Corinthians 4:4), He brings men's minds captive in obedience to Christ (John 16:8-11). Thus Paul's weapons are the weapons of the power of God which apply the truth of the cross and of the crucified One to men and women (1 Corinthians 1:18; 1 Corinthians 2:2; 1 Corinthians 2:4-5). And these are the weapons available to all who are truly His.