Known sourcecanonical
"I slept, and dreamed that life was Beauty; I woke, and found that life was Duty. Was thy dream then a shadowy lie? Toil on, poor heart, unceasingly; And thou shalt find thy dream to be A truth and noonday light to thee."
Ellen Sturgis Hooper / Life a Duty.
Life a Duty.
Bartlett's Familiar Quotations, 9th ed. (Little, Brown, 1905), public domain