The more tranquil a man becomes, the greater is his success, his influence, his power for good. Calmness of mind is one of the beautiful jewels of wisdom.
James Allen (1864-1912) British-born American essayist.
There is no such thing as perpetual tranquillity of mind while we live here; because life itself is but motion, and can never be without desire, nor without fear, no more than without sense.
Thomas Hobbes (1588-1679) British philosopher.
Tranquility is the old man's milk.
Thomas Jefferson (1743-1826) Third president of the United States.