The Bodhisatta was once a fish. One year there was a terrible drought and his pond dried up, forcing all the fish and turtles to bury themselves in the mud to stay alive. Birds flocked here to pick them out with their beaks and eat them. Knowing that only he could save them, the Bodhisatta climbed out of the mud and spoke an Act of Truth (a solemn declaration of one’s supreme virtue followed by a command or request) to the rain god, telling about his lifetime of virtue and begging for rain to save the lives of those living in the pond. His request was answered and heavy rain filled the pond.
In the Lifetime of the Buddha
There was a terrible drought across the land; crops withered and lakes dried up and the Buddha decided he needed to do something. When he came back to the monastery from his morning alms round, he stood on the steps of the dried-up pool where he usually bathed (which was built from the exact pond where he had previously lived as a fish) and told Ananda, one of his top disciples, to bring his bathing robe. Ananda brought it, but wondered what the Buddha was thinking, because the pool had no water, only mud. The Buddha put it on and said “I wish to bathe.” The throne of Indra, king of the gods, became warm and he looked out to see what was happening. Seeing the Buddha, he ordered the rain god to send a deluge and end the drought, and it lasted until the water in the Buddha’s pool rose to the topmost step.
When he later heard some of his disciples singing his praises, the Buddha told his disciples this story so they knew it was not the first time he had made it rain.
The rain god was an earlier birth of Ananda and the fish were earlier births of the Buddha’s disciples.