* Okay, here goes:
"The best-laid schemes o' mice an' men
Gang aft agley."
"For you yourselves know perfectly that the day of the Lord cometh like a thief in the night."
"In the midst of life, we are in death."
Or, edging into inspirational poster territory:
"Live each day like it could be your last."
If you've read the novel, you'll see how ridiculous these seem, and what a joke they make of the whole enterprise of boiling the novel down to a pithy statement.