The Bodhisatta was once an ascetic who lived in the Himalayas and did walking meditation all night long. A tree fairy who lived at the end of his walking path respected him and one day asked him two questions. “Who wakes when others sleep and sleeps when others wake,” she riddled. The Bodhisatta answered correctly that it was he. Then the tree fairy asked him, “How do you do it?” and the Bodhisatta said it was because he was dedicated to living with virtue. Pleased with the Bodhisatta’s answers, the tree fairy went back to her tree.
In the Lifetime of the Buddha
A layman who was very devoted to the Buddha was traveling with a trade caravan. One night as he did walking meditation, a band of thieves surrounded their camp and waited for him to go to sleep, but he did not. At dawn the thieves threw down their weapons and left empty-handed, telling the caravan leader he owed his life and property to the man who didn’t sleep. All the caravan workers thanked him for saving their lives.
When he next saw the Buddha, the lay follower recounted what had happened and the Buddha told him this story so he knew he himself had also once gained great merit by doing walking meditation all night.
The tree fairy was an earlier birth of Uppalavanna, one of the Buddha’s top female disciples.