The Bodhisatta was once a lion. He mated with a jackal and the cub looked like his father in every way, but it sounded like his mother. One day the lions of his pride were playing and having fun, roaring loudly as lions do. When the Bodhisatta’s half-jackal cub tried to roar, out came a jackal’s howl and all the other lions fell silent. One of the Bodhisatta’s other cubs asked his father who the strange sounding lion was. The Bodhisatta told him this was his half-brother, the son of a jackal. Then he told his half-jackal son to not speak again or the rest of the pride would know what he really was. The cub took the advice and never tried to roar again.
In the Lifetime of the Buddha
The half-jackal cub was an earlier birth of a dimwitted disciple of the Buddha who was completely unaware how stupid he was. He made it known to other disciples that someday he wanted to recite scripture at assembly, and he was invited to do it. That evening he took his seat in the jeweled pavilion in front of the others, and just as he was to begin speaking he grew nervous and ashamed. He got the first verse out, but could not remember the second, so he left and went to be alone in his quarters.
Later, when the Buddha heard some disciples discussing the incident, he told them this story so they knew that this empty disciple had also betrayed himself by speaking in the past.
The Bodhisatta’s other cub was an earlier birth of the Buddha’s son.