At Sāvatthi.

"Bhikkhus, suppose there were a spear with a sharp blade. Then a man might come along and say, 'I will grasp this sharp-bladed spear with my hand or fist, bend it back, twist it out of shape, and roll it back.'

What do you think, bhikkhus? Would that man be able to grasp, twist, or roll back that sharp-bladed spear with his hand or fist?"

"No, venerable sir."

"For what reason?"

"Because, venerable sir, the sharp-bladed spear cannot easily be grasped, twisted, or rolled back with the hand or fist. And moreover, the only result for that man would be weariness and distress."

"In the same way, bhikkhus, if any bhikkhu has developed, practiced often, made a vehicle, made a basis, firmly established, nurtured, and resolutely undertaken the release of mind through loving-kindness, and a non-human being were to think, 'I will agitate this bhikkhu's mind,' that non-human being would only end up weary and distressed."