2 Corinthians 10:3–6 (ESV): 3 For though we walk in the flesh, we are not waging war according to the flesh. 4 For the weapons of our warfare are not of the flesh but have divine power to destroy strongholds. 5 We destroy arguments and every lofty opinion raised against the knowledge of God, and take every thought captive to obey Christ, 6 being ready to punish every disobedience, when your obedience is complete.
Reading 1 and 2 Corinthians indicates that there are two letters that were not preserved. In 1 Corinthians Paul sought to correct many spiritual abuses in the church. It appears that the first reaction of the church was to disregard Paul and rebel against his authority.
In a letter he wrote between 1 and 2 Corinthians, it appears that Paul was even harsher in condemning sin and unspiritual practices of the people. God finally got through to the people and they repented.
In 2 Corinthians Paul sought to assure the people of his love and reconcile with them. In this letter, the apostle was very vulnerable with the people.
Yet in 2 Corinthians 10, Paul again defended his ministry against those who argued that he was bluffing and not in line with the Spirit. So Paul wrote this powerful set of verses.
There are many ways to wage war by the flesh: political manipulations, bribery, gossip, slander, threats, flattery, etc.
The follower of Christ instead wages war in the Spirit, destroying arguments and opinions raised against God, taking all thoughts captive to obey Christ.
Heavenly Father, help me to wage war in and by the Spirit, even though we live in world that operates by the flesh. Amen.