There are a number of qualities which are important for mental peace, but from the little experience I have, I believe that one of the most important factors is human compassion and affection: a sense of caring.
The meek man is not a human mouse afflicted with a sense of his own inferiority. He has accepted God's estimate of his own life: In himself, nothing; In God, everything. He knows well that the world will never see him as God sees him and he has stopped caring.
There is a word in South Africa - Ubuntu - that describes his greatest gift: his recognition that we are all bound together in ways that can be invisible to the eye; that there is a oneness to humanity; that we achieve ourselves by sharing ourselves with others, and caring for those around us.
If you shift your focus from yourself to others, extend your concern to others, and cultivate the thought of caring for the well being of others, then this will have the immediate effect of opening up your life and helping you to reach out.
Let us simmer over our incalculable cauldron, our enthralling confusion, our hotchpotch of impulses, our perpetual miracle - for the soul throws up wonders every second. Movement and change are the essence of our being; rigidity is death; conformity is death; let us say what comes into our heads, repeat ourselves, contradict ourselves, fling out the wildest nonsense, and follow the most fantastic fancies without caring what the world does or thinks or says. For nothing matters except life.
The modern world has far too little understanding of the art of keeping young. Its notion of progress has been to pile one thing on top of another, without caring if each thing was crushed in turn. People forgot that the human soul can enjoy a thing most when there is time to think about it and be thankful for it. And by crowding things together they lost the sense of surprise; and surprise is the secret of joy.
What distinguishes our species is thought. The cerebral cortex is in a way a liberation. We need no longer be trapped in the genetically inherited behavior patterns of lizards and baboons: territoriality and aggression and dominance hierarchies. We are each of us largely responsible for what gets put in to our brains. For what as adults we wind up caring for and knowing about. No longer at the mercy of the reptile brain we can change ourselves. Think of the possibilities.