James 4:5

in vain--No word of Scripture can be so. The quotation here, as in Eph 5:14, seems to be not so much from a particular passage as one gathered by James under inspiration from the general tenor of such passages in both the Old and New Testaments, as Num 14:29; Pro 21:20; Gal 5:17. spirit that dwelleth in us--Other manuscripts read, "that God hath made to dwell in us" (namely, at Pentecost). If so translated, "Does the (Holy) Spirit that God hath placed in us lust to (towards) envy" (namely, as ye do in your worldly "wars and fightings")? Certainly not; ye are therefore walking in the flesh, not in the Spirit, while ye thus lust towards, that is, with envy against one another. The friendship of the world tends to breed envy; the Spirit produces very different fruit. ALFORD attributes the epithet "with envy," in the unwarrantable sense of jealously, to the Holy Spirit: "The Spirit jealously desires us for His own." In English Version the sense is, "the (natural) spirit that hath its dwelling in us lusts with (literally, 'to,' or 'towards') envy." Ye lust, and because ye have not what ye lust after (Jam 4:1-2), ye envy your neighbor who has, and so the spirit of envy leads you on to "fight." James also here refers to Jam 3:14, Jam 3:16.

— Jamieson-Fausset-Brown Commentary (public domain)