The Bodhisatta was once a quail. Just after hatching, while still too young to walk or fly, a forest fire swept toward his nest. Unable to flee as all the other animals had, including his parents, the Bodhisatta performed an act of truth (a solemn declaration of one’s supreme virtue followed by a request for some miraculous result). As he did this, the flames miraculously never got closer to him than sixteen lengths.
In the Lifetime of the Buddha
One day while the Buddha was out on a morning alms round in the same place that he had lived as the quail, a forest fire broke out. Some new disciples began to start a counter fire to burn some ground now that would serve as a place of safety when the big fire arrived. The experienced disciples mocked them and told them to stop; all they needed to do was seek safety from the Buddha. They walked to the specific spot in the forest, gathered around the Buddha, and the roaring flames got no closer than sixteen lengths.
After the fire was extinguished, the Buddha told them this story so they knew that what had just happened was not due to his present powers, but because he had performed an act of truth at this very spot in the past and no flames would burn it for an eon.
The quail parents were earlier births of the Buddha’s father and birth mother.