Remember, today is the tomorrow you worried about yesterday.
Dale Carnegie (1888-1955) American writer, lecturer
How to Stop Worrying and Start Living, Part 10 “How I Conquered Worry” (1948)
(Source)
Final note by Carnegie on the story "Six Major troubles Hit Me All At Once" by C. I. Blackwood of Oklahoma City.
The phrase was a "rule" Carnegie taught in his adult courses, and he collected many reports from students about how the various rules taught in the course actually worked in their lives. Thus the "remember" above and how the phrase is also mentioned, quoted in the past tense, in the story "I Now Look for the Green Light," by Joseph M. Cotter of Chicago: "I was told over and over that 'today was the tomorrow I had worried about yesterday.'"
