Gospel of peace
In a sin-cursed world, full of tragedy, heartache, and war, there is only one place to find peace. It's in the person of the Lord Jesus Christ, with a saving relationship with Him.
Philippians 4:7 And the peace of God, which passeth all understanding, shall keep your hearts and minds through Christ Jesus.
If you're a Christian that wants more peace in this world, then get busy preaching the saving gospel of peace.
Romans 10:15 And how shall they preach, except they be sent? as it is written, How beautiful are the feet of them that preach the gospel of peace, and bring glad tidings of good things!