קבלה אויף תהילים 73:3

contains an allusion to the kindred term used formerly by David when he said: “For I was envious of the madmen (holelim)” (Ps. 73, 3). God thus said in effect to David: “As thou livest, since thou enviest madmen, thou thyself wilt yet be driven to play the madman”; and so it came to pass when he was brought before Achish and his life was in danger; he then “feigned himself mad (vayitholel) in their hand”, that is, he behaved like one of those madmen (holelim) whom he had once envied; and only then did the Shekinah come to his rescue.