Abstemius's Fables (Sir Roger L'Estrange)
294. (Abstemius 42) Oxen and Timber.
Why don't you run and make haste? cry'd the Timber in the Cart, to the Oxen that drew it: The Burthen is not so heavy, sure. Well! (said the Oxen) if you did but know your own Fortune, you'd never be so merry at ours. We shall be discharged of our Load so soon as we come to our Journey's End, but you that are design'd for Beams and Supporters, shall be made to bear till your Hearts break. This Hint brought the Timber to a better understanding of the Case.
'Tis matter of Humanity, Honour, Prudence, and Piety, to be tender of one another: for no Man living knows his End, and 'tis the Evening that crowns the Day.
Fables of Aesop and Other Eminent Mythologists: Abstemius's Fables by Sir Roger L'Estrange. Available online at Google Books.