Bitter envying, ζῆλος in itself may be either good or bad, and therefore πικρόν is added to characterize it. Bishop Lightfoot (on Galatians 5:20) points out that "as it is the tendency of Christian teaching to exalt the gentler qualities and to depress their opposites, ζῆλος falls in the scale of Christian ethics (see Clem. Romans, §§ 4-6), while ταπεινότης, for instance, rises." It may, perhaps, be an incidental mark of early date that St. James finds it necessary to characterize ζῆλος as πικρόν. Where St. Paul joins it with ἐριθείαι and ἔρις there is no qualifying adjective (Romans 13:13; 1 Corinthians 3:3; 2 Corinthians 12:20; Galatians 5:20). (On the distinction between ζῆλος and φθόνος, both of which are used by St. James, see Archbishop Trench on 'Synonyms,' § 26). Strife ( ἐριθείαν); better, party spirit, or faction (cf. Romans 2:8; 2 Corinthians 12:20; Galatians 5:20; Philippians 1:17; Philippians 2:3). The A.V. "strife" comes from a wrong derivation, as if ἐριθεία were connected with ἔρις, whereas it really comes from ἔριθος, a hired laborer, and so signifies
Glory not; i.e. glory not of your wisdom, a boast to which your whole conduct thus gives the lie.