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. (John 14: 27)
The peace that Christ speaks of is not of this world.
It is a peace that this world does not understand.
Quite literally, the Lord Himself is our Peace. He is even called, the Prince of Peace, in Isaiah. And He has made peace for us through the blood of His cross.
And having made peace through the blood of his cross, by him to reconcile all things unto himself; by him, I say, whether they be things in earth, or things in heaven. (Colossians 1:20)