Eireneuo means to be at peace, to live in peace with others, or to keep peace. It is the verbal form of eirene (peace). The New Testament uses it in calls to pursue peace with others (Mark 9:50; Romans 12:18; 1 Thessalonians 5:13; 2 Corinthians 13:11).
Peace in the New Testament is both a gift received (the peace of God — Philippians 4:7) and a discipline pursued (eireneuo — live peaceably with all). The call to pursue peace reflects the character of God who is the 'God of peace' (Philippians 4:9; Romans 15:33; Hebrews 13:20). Romans 12:18's qualification 'as far as it depends on you' acknowledges realism — not all conflict can be resolved — while refusing to use that as an excuse for negligence. The Beatitude 'Blessed are the peacemakers' (Matthew 5:9) elevates active peace-pursuing as a mark of divine sonship.