The Greek verb eirēnopoieō means to make peace — an active, intentional activity of bringing about reconciliation and harmony. It combines eirēnē (peace) with poieō (to make/do). In Colossians 1:20, Paul uses it to describe the cosmic peacemaking accomplished by Christ through His cross.
The Colossian use of eirēnopoieō is one of the most expansive statements of atonement in the New Testament: Christ 'making peace (eirēnopoieō) by the blood of his cross' — reconciling all things in heaven and on earth. This cosmic peacemaking is the basis for the beatitude in Matthew 5:9: 'Blessed are the peacemakers (eirēnopoios).' Those who make peace in human relationships reflect the activity of the God who in Christ reconciled the cosmos to Himself.