佛垂般涅槃略說教誡經 1.12

1.12

“You monks, if you are diligent and energetic, nothing is difficult. Therefore, you should be diligent and energetic, just as a small stream of water flowing constantly can pierce stone. If a practitioner's mind frequently becomes lax and slack, it is like rubbing sticks for fire and stopping before they grow hot; though one wants to get fire, fire is hard to obtain. This is called vigor.