Eirene is the Greek word for peace, and in the New Testament it carries all the fullness of the Hebrew shalom behind it — not merely the absence of conflict, but wholeness, well-being, and reconciliation. It describes peace with God, secured through Christ, and the peace of God that guards the heart in every circumstance.
Jesus left this peace as a parting gift: not as the world gives, give I unto you. The world's peace depends on calm surroundings; Christ's peace holds in the storm. Paul says it passes understanding — it does not make sense of the circumstances so much as rise above them, keeping heart and mind steady in Christ Jesus.
Eirene in Scripture
Peace I leave with you, my peace I give unto you: not as the world giveth, give I unto you. Let not your heart be troubled, neither let it be afraid.