The Greek adjective hagnos means pure, chaste, morally clean, or innocent. It occurs 8 times in the New Testament and describes a purity that is inward and motivational, not merely external ritual cleanness. It is related to hagios (holy) and shares the same root concept of being set apart and undefiled.
Hagnos carries the sense of unstained integrity — purity of motive, conscience, and conduct. James 3:17 lists it as the first quality of heavenly wisdom: 'the wisdom that comes from heaven is first of all pure (hagnē).' Paul urges Timothy to 'keep yourself pure (hagnon)' (1 Timothy 5:22) and exhorts believers to think on 'whatever is pure (hagna)' (Philippians 4:8). John's eschatological use is striking: 'Everyone who has this hope in him purifies himself, just as he is pure (hagnos)' (1 John 3:3) — the coming of Christ calls believers to present-tense purity modeled on Christ's own perfect purity.