Albert Barnes Commentary 2 Corinthians 10:3

"For though we walk in the flesh, we do not war according to the flesh" — 2 Corinthians 10:3 (ASV)

For though we walk in the flesh. Though we are mortal like other people; though we dwell, like them, in mortal bodies and must necessarily devote some care to our temporal needs; and though, being in the flesh, we are conscious of imperfections and frailties like others. The meaning is that he did not claim exemption from the common needs and frailties of nature. The best of people are subject to these needs and frailties; the best of people are liable to err.

We do not war after the flesh. The warfare in which he was engaged was with sin, idolatry, and all forms of evil. He means that in conducting this, he was not motivated by worldly views or policy, or by such ambitious and self-interested aims as controlled the people of this world. This refers primarily to the warfare in which Paul himself was engaged as an apostle; and the idea is that he went out as a soldier under the great Captain of his salvation, to fight His battles and to make conquests for Him. A similar allusion occurs in 2 Timothy 2:3–4.

It is true, however, that not only all ministers but all Christians are engaged in a warfare; and it is equally true that they do not maintain their conflict after the flesh, or on the principles that govern the people of this world. The warfare of Christians relates to the following points:

1. It is a warfare with the corrupt desires and sensual propensities of the heart; with internal corruption and depravity; with the remaining unsubdued propensities of a fallen nature.
2. With the powers of darkness—the mighty spirits of evil that seek to destroy us. .
3. With sin in all forms; with idolatry, sensuality, corruption, intemperance, and profanity, wherever they may exist. The Christian is opposed to all these, and it is the aim and purpose of his life, as far as he is able, to resist and subdue them. He is a soldier, enlisted under the banner of the Redeemer, to oppose and resist all forms of evil. But his warfare is not conducted on worldly principles. Mohammed propagated his religion with the sword, and the people of this world seek victory by arms and violence. The Christian looks for his conquests only by the force and power of truth and by the agency of the Spirit of God.