首楞嚴義疏注經 8.526

8.526

始因貪欲，鬼受魃形，上為畜生災咎之應。業盡復本，參在愚類，以欲多者不習別善，但專一境。由不習善，故招愚鈍。頑、愚別者，頑謂知善不從，罔受教誨。愚謂瞑然昏暗，識鈍難明，有此異耳。

Their initial cause was greed and desire, so as ghosts they underwent the form of drought demons, and above as animals they corresponded to portents of disaster. When their karma was exhausted and they returned to their original [destiny], they mingle with the category of the foolish. Because those with much desire do not practice other virtues but focus only on a single domain, by not practicing virtue they incur dull-witted foolishness. The difference between the obstinate and the foolish is: 'obstinate' means knowing good yet not following it and refusing to receive instruction; 'foolish' means being dim and darkened, with dull cognition difficult to enlighten. It is simply this difference.