We all want peace in our lives -- but sometimes we confuse external peace with internal peace!
God promised us peace, but it is often peace in our hearts. Jesus said, "Peace I give to you, my peace I give unto you; not as the world gives, give I unto you."
In this life, we may not always have peace around us. There can be conflicts; there are still people who do evil, and things can go wrong. Even nations can rise against other nations and rulers against each other.
One thing we can have is the peace of God ruling in our hearts. We want everything to go well externally, and that is a good goal and we should pray and work to that end. But even when not everything goes according to our plan, we can have the peace and joy of God in our hearts.
The source of that peace and joy is not our external circumstances, but God's Holy Spirit dwelling in our lives. The Bible says the fruits of the Holy Spirit include peace and joy. Jesus Himself in our lives is our source of peace! So His peace He gives us; not as the world gives does Jesus give us His peace by the power of the Holy Spirit.