At Savatthi. “Bhikkhus, suppose there was a mountain river sweeping downwards, flowing into the distance with a swift current. If on either bank of the river kasa grass or kusa grass were to grow, it would overhang it; if rushes, reeds, or trees were to grow, they would overhang it. If a man being carried along by the current should grasp the kasa grass, it would break off and he would thereby meet with calamity and disaster; if he should grasp the kusa grass, it would break off and he would thereby meet with calamity and disaster; if he should grasp the rushes, reeds, or trees, sn.iii.138 they would break off and he would thereby meet with calamity and disaster.
“So too, bhikkhus, the uninstructed worldling … regards form as self, or self as possessing form, or form as in self, or self as in form. That form of his disintegrates and he thereby meets with calamity and disaster. He regards feeling as self … perception as self … volitional formations as self … consciousness as self, or self as possessing consciousness, or consciousness as in self, or self as in consciousness. That consciousness of his disintegrates and he thereby meets with calamity and disaster.
“What do you think, bhikkhus, is form permanent or impermanent?”—“Impermanent, venerable sir.”…—“Therefore … Seeing thus … He understands: ‘… there is no more for this state of being.’”