Peace is the nature of the soul. Whenever you receive any happiness, it is from the soul and not from this world.
We think that happiness has come from an object but happiness actually comes from within.
Like when a dog keeps chewing on a bone his mouth starts bleeding and he thinks the bone is very juicy. It is not the bone that is juicy. Lord Krishna has beautifully said in the Bhagavad Gita, ‘Anityam Asukham Lokam Imam Prapyam Bhajsamah’. This world is transient and there is no pleasure in it, after attaining it, look towards me. Dissolve in me, chant my name; only then will the mind be at peace.