Siman 494

(51.) And even though he said these words in jest — in truth, there is substance in them. And there is in this matter very great depth and very profound secret. For all his words — even his witticisms and jokes — all of them contain profound, awesome, and very deep secrets. And even a simple person who has some genuine intellect can understand from them some wondrous and awesome hints. (Said the transcriber: See Likutay vol. 1, Torah 12 in the discourse Tehillah l'David, and in Likutay Halachos, Laws of Talmud Torah...)