AN 2.98
PTS: A i 83
II,x,1
Bala Sutta: Fools
translated from the Pali by
Thanissaro Bhikkhu

"Monks, these two are fools. Which two? The one who takes up a burden that hasn't fallen to him, and the one who doesn't take up a burden that has. These two are fools."

See also: AN 2.21.