As he neared a grove of trees, he met the Buddha coming from it. The Buddha smiled and took his hand. Together they went to a temple where two old monks were sweeping the floor. The Buddha said to them: "This young monk will live here with you from now on. Continue your sweeping, and as your brooms move back and forth, say the two-syllable mantra that I will now give you. Don't stop until I come back."
The young monk sat down and listened to the movement of the brooms, to and fro over the floor. He heard the whispered rhythm of the mantra as it was repeated over and over again. This went on for many weeks, and before the Buddha came back, the young monk had found full liberation and so had the two old monks.