The simple meaning of the word peace of the soul is the condition in which the soul is already at the stage of true calm, feeling of air, no pressure, accepting reality, letting himself in the Creator, can feel the sweetness of faith, be self-controlling and lustful, away from hate, tranquil and the heart becomes wide and loose.
Humans who have been able to reach this stage of peace of soul are human beings who understand the nature of life, have mengertia what to do and what to avoid. And generally, man will become more calm if he is near his Creator, if humans already know and believe that there is a tremendous power in this realm that transcends any power and only HE is the most powerful over him and everything around him. And that is the essence of the creation of this soul for all creatures, the soul will always seek the ultimate truth about the creator's figure and the soul will feel calm if it has found and made the creator as the main back of his life. Wherever that soul goes and hides, the soul will always seek the ultimate truth, for that is the essence of the creation of the soul.