American cartoonist Bill Watterson wrote a popular line in the comic strip Calvin & Hobbes:
 
“God put me on this Earth to accomplish a certain number of things. Right now I am so far behind I will never die.”
 
The date of the comic strip is not known, but the expression began to be cited by February 1993.
 
     
Wikipedia: Bill Watterson
William Boyd “Bill” Watterson II (born July 5, 1958) is an American cartoonist and the author of the comic strip Calvin and Hobbes, which was syndicated from 1985 to 1995. Watterson stopped drawing Calvin and Hobbes at the end of 1995 with a short statement to newspaper editors and his readers that he felt he had achieved all he could in the medium.
 
28 February 1993, The Star (Crete, IL), “Political Bytes” by Myra Guindon, pg. A-7, col. 2:
Quoth the photocopied message: “God put me on this Earth to accomplish a certain number of things. Right now I am so far behind I will never die.”
       
Google News Archive
2 May 1993, Spartanburg (SC) Herald-Journal, “The Stroller” by Lou Parris, pg. B1, col. 1:
Notice on a hospital surgery room bulletin board: “God put me on this Earth to accomplish a certain number of things. Right now I am so far behind I will never die.”
 
Google News Archive
26 August 1993, Milwaukee (WI) Sentinel, “‘Aching’ (and deceased) golfer doesn’t want St. Peter’s help” by Alex Thien, pg. 3C, col. 2:
When he got back to work, he set up a little desk sign:
 
“God put me on this Earth to accomplish a certain number of things. Right now I am so far behind I will never die.”
 
January 1994, Nation’s Restaurant News, “Boyd Morris: A rose-colored world” by Robin Allen, pg. 136:
In his 12 years with K&W, Morris has helped open 17 units of the 31-unit chain. And for now he doesn’t plan to stop helping. Those who ask why receive a cartoon that reads: “God put me on this earth to accomplish a certain number of things. Right now I’m so far behind I’ll never die.”
   
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POUNCE the Cat
4/25/94
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Kenneth Hriensaitong (.(JavaScript must be enabled to view this email address))
“God put me on Earth to accomplish a certain number of things. 
Right now, I am so far behind I will never die.”
-Calvin, “Calvin & Hobbes”
 
Google Books
Nursing Case Management:
A Practical Guide to Success in Managed Care
By Suzanne K. Powell and Patty M. Wekell
Philadelphia, PA: Lippincott-Raven
1996
Pg. 305:
Not far from the Ann Landers column, I have a picture of a disgruntled-looking little guy saying, “God put me on this earth to accomplish a certain number of things. Right now I am so far behind I will never die.”
 
Google Books
Happiest You Ever:
365 Ways to Invite More Love, Sex, Fun, Friendship, Fellowship, Community, and Career Satisfaction Into Your Life - Each and Every Day!
By Meera Lester, Carolyn Dean MD and Susan B. Townsend
Avon, MA: Adams Media
2011
Pg. 104:
“God put me on this earth to accomplish a certain number of things. Right now I am so far behind that I will never die.” —Bill Watterson
 
Google Books
The 2,548 Wittiest Things Anybody Ever Said
By Robert Byrne
New York, NY: Touchstone
2012
Pg. ?:
1,359
God put me on this earth to accomplish a certain number of things. I’m so far behind I will never die. —Bill Watterson