4. A confutation of those who try to propagate their creed by force and persecution (compare Lu 9:54-56).
weapons—for punishing offending members (2Co 10:6; 1Co 4:21; 5:5, 13); boldness of speech, ecclesiastical discipline (2Co 10:8; 2Co 13:10), the power of the word, and of the sacraments, the various extraordinary gifts of the Spirit.
carnal—Translate, "fleshly," to preserve the allusion to 2Co 10:2, 3.
mighty through God—Greek, "mighty to God," that is, mighty before God: not humanly, but divinely powerful. The power is not ours, but God's. Compare "fair to God," that is, divinely fair (Ac 7:20, Margin). Also above (2Co 2:15), "unto God a sweet savor." "The efficacy of the Christian religion proves its truth" [Bengel].
pulling down—As the Greek is the same as in 2Co 10:5, translate, "casting down." Compare Jer 1:10: the inspired servants of God inherit the commission of the Old Testament prophets.
strongholds—(Pr 21:22); namely, in which sinners entrench themselves against reproof; all that opposes itself to Christ; the learning, and eloquence, and philosophical subtleties on which the Corinthians prided themselves. So Joshua's trumpet blast was "mighty" under God to overthrow the walls of Jericho.