首楞嚴義疏注經 4.274

4.274

"Just as with Yajñadatta in that city, what causes and conditions were there for him to be terrified of [losing] his head and run about? When his madness suddenly ceased, his head was not obtained from outside; even when his madness had not yet ceased, when had it ever been lost? Pūrṇa! The nature of delusion is just like this: where does its cause reside?"