“May your soul be in heaven before the devil knows you’re dead” is an old Irish toast of uncertain origin. ““May yer sowl be in glory a fortnight before the divil knows you’re dead” was cited in an 1869 book. “May you be in heaven three weeks before the devil knows you’re dead” was cited in an 1869 newspaper. The length of time in heaven varies from hours to days.
 
   
Google Books
Autobiography and Personal Recollections of J. B. Gough
Springfield, MA: Bill, Nichols & Co.
1869
Pg. 485:
“May yer sowl be in glory a fortnight before the divil knows you’re dead.”
 
28 June 1869, Daily Evening Traveller (Boston, MA), “A Flying Visit to Berkshire,” pg 2, col. 4:
“May you live forever!” or carry it out with a benediction from your Emerald Isle, “May you be in heaven three weeks before the devil knows you’re dead.”
 
Chronicling America
5 December 1879, New York (NY) Herald, “Church Fairs,” pg. 6, col. 6:
He said that Father McDowell had brought him there to give his blessing to the fair, and this was it, “May you be six months in heaven before the devil knows you’re dead.”
 
Google Books
Waes Hael: A Collection of Toasts Crisp and Well Buttered
By Edithe Lea Chase and Capt. W. E. P. French, U. S. A.
New York, NY: The Grafton Press
1903
Pg. 93:
May your sowl be in glory three weeks before the divil knows you’re dead.
Unknown
 
Google Books
“By the eternal”: a novel
By Opie Percival Read
Chicago, IL: Laird & Lee, Publishers
1906
Pg. 87:
“I wouldn’t injure you for the world, sir,” he declared, and then added: “And as they say in old Ireland, may your soul be in heaven before the devil knows you’re dead.”
 
18 March 1935, Boston (MA) Daily Globe, “Will Rogers’ Dispatch,” pg. 1, col. 8:
Today I am dipping my Shamrock into a thimbleful of old Irishowen, and may you be seven months in Heaven before the devil knows you’re dead. Fag a bealach. Yours, WILL ROGERS.
   
Google Books
Irish Wit & Wisdom
By John Hickey
Lincolnwood, IL: Publications International
1998        
Pg. 153:
Health and long life to you.
The wife (or husband) of your choice to you.
A child every year to you.
Land without rent to you.
And may you be half-an-hour in heaven before the devil knows you’re dead. — Irish toast
 
Google Books
Great Toasts:
From Births to Weddings to Retirement Parties—and Everything in Between
By Andrew Frothingham
Franklin Lakes, NJ: Career Press
2002
Pg. 164:
May you have food and raiment,
A soft pillow for your head,
May you be forty years in heaven
Before the devil knows you’re dead.
 
Google Books
Before the Devil Knows You’re Dead
By Michael Ledwidge
New York, NY: Atria Books
2003
Pg. ?:
May the road rise to meet you
May the wind be always at your back
And may you be half an hour in heaven
Before the Devil knows you’re dead — Irish Toast
 
OCLC WorldCat record
”—Before the devil knows you’re dead” : Irish blessings, toasts and curses
Author: Padraic O’Farrell
Publisher: Cork : Mercier, ©2005.
Edition/Format:   Print book : English
 
Wikipedia: Before the Devil Knows You’re Dead
Before the Devil Knows You’re Dead is a 2007 crime drama film directed by Sidney Lumet, his last feature film before his death in 2011.
 
The film was written by Kelly Masterson, and stars Philip Seymour Hoffman, Ethan Hawke, Marisa Tomei, and Albert Finney. The title comes from the Irish saying: “May you be in heaven a full half-hour before the devil knows you’re dead”. The film unfolds non-linearly, repeatedly going back and forth in time, with some scenes shown from various points of view.
 
Google Books
Movies and Mental Illness:
Using Films to Understand Psychopathology
By Danny Wedding and Ryan M. Niemiec
Boston, MA: Hogrefe Publishing
2014
Pg. ?:
The film’s unique title comes from a famous Irish toast: “May you have food and raiment; a soft pillow for your head; may you be 40 years in heaven; before the devil knows you’re dead.”
 
Twitter
ℰℳ‏
@emfarrah
May you have food & clothing,
A pillow to rest your head,
And forty years in heaven,
Before the devil knows you’re dead.
#IrishPrayer 🍀
12:28 PM - 25 Sep 2015