3. envying—jealousy, rivalry. As this refers to their feelings, "strife" refers to their words, and "divisions" to their actions [Bengel]. There is a gradation, or ascending climax: envying had produced strife, and strife divisions (factious parties) [Grotius]. His language becomes severer now as He proceeds; in 1Co 1:11 he had only said "contentions," he now multiplies the words (compare the stronger term, 1Co 4:6, than in 1Co 3:21).
carnal—For "strife" is a "work of the flesh" (Ga 5:20). The "flesh" includes all feelings that aim not at the glory of God, and the good of our neighbor, but at gratifying self.
walk as men—as unregenerate men (compare Mt 16:23). "After the flesh, not after the Spirit" of God, as becomes you as regenerate by the Spirit (Ro 8:4; Ga 5:25, 26).