"Nobody grows old by merely living a number of years; people grow old by deserting their ideals. Years may wrinkle the skin, but to give up enthusiasm wrinkles the soul.
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You are as young as your faith, as old as your doubt; as young as your self-confidence, as old as your fear, as young as your hope, as old as your despair." - Samuel Ullman

Son poème "Youth" en anglais