The agrapha are sayings attributed to Jesus that were not recorded in the four gospels. This agraphon is clever and witty and Jesus probably never said it, but it is funny nonetheless. It is attributed to Jesus by the Muslim intellectual al-Ghazali:
Jesus (peace upon him) said: "Even though I managed to raise the dead, I have never been able to cure an idiot!"
(in Bradley J. Cook, Classical Foundations of Islamic Educational Thought [Provo, Utah: Brigham Young University Press, 2010], 103)
Parents and teachers can sometimes relate.