Greek zelos, zeal / ardor / jealousy, an NT term carrying both positive and negative valence depending on context. In positive sense, zelos is the fervent earnestness appropriate to a righteous cause: the Lord Jesus's zeal for the LORD's house (John 2:17, citing Psalm 69:9, The zeal of thine house hath eaten me up); Paul's zeal for the Galatians (Galatians 4:18, it is good to be zealously affected always in a good thing); the Lord's commendation of the church's first works versus the Laodicean lukewarmness (Revelation 3:15-16, 19, be zealous therefore, and repent). In negative sense, zelos is the rivalrous jealousy that destroys community: Paul's catalog of works of the flesh (Galatians 5:20-21, emulations, wrath, strife, seditions, heresies, envyings); James's diagnosis of wars and fightings among believers (James 3:14-16; 4:1-2). The Pharisee Saul before his conversion was characterized by Christ-persecuting zelos (Philippians 3:6, concerning zeal, persecuting the church); Paul converted retains zealous earnestness now directed to the gospel (Romans 10:2, the diagnostic line: I bear them record that they have a zeal of God, but not according to knowledge). The patriarchal-Reformed reader recovers zelos as the fervent earnestness appropriate to the LORD's cause — bound to truth, ordered under wisdom, expressed in obedient action, and distinguished from both spiritually-tepid lukewarmness and rivalrous-fleshly jealousy.