The full account of this lifetime is told in the Vidhurapandita Jataka (#545), while the Catu-Posathika Jataka only relates this single incident from that story.
The Bodhisatta was once a king’s advisor. Four great kings—a naga king; a garuda king; Indra, king of the gods; and the Bodhisatta’s king—were friends in their previous lives, and one day, after keeping the holy-day fast and meditating, they sat down to chat. Indra wondered what their greatest virtues were. The naga king said he had great patience: garudas are the mortal enemies of nagas, but anger never arose in him when he saw one. The garuda king said he possessed great self-restraint: nagas are the garudas’ favorite food, but he remained hungry rather than kill and eat one. Indra said he kept great abstinence from desire: he left behind the glory of heaven, where every sort of happiness can be found, and came to earth to focus on the holy day. The human king said he maintained great devotion to religious perfection: he went to his park to observe the holy day instead of letting loose in his harem, which had sixteen thousand dancing girls.
Each king felt his virtue was superior to the others, so they went to the palace to ask the Bodhisatta which of them was truly the greatest. After all four kings shared their stories of virtue, the Bodhisatta declared them equal, like the spokes of a wheel. All greatly pleased with this answer, they praised the Bodhisatta’s incomparable wisdom and gave him gifts: a jewel (the naga king), a golden garland (the garuda king), a robe made of heavenly silk (Indra), and one thousand cows (the human king).
In the Lifetime of the Buddha
One day some of the Buddha’s disciples were discussing his supreme wisdom; in particular, how he was so quick-witted that he always crushed his opponents’ arguments, even reducing revered sages to silence. When the Buddha heard them talking about it, he said it was no big deal that he could convince others because he had reached enlightenment. Then he told them this story so they knew that he’d also been able to do the same in the past.
Indra, the naga king, the garuda king, and the Bodhisatta’s king were earlier births of Anuruddha, Sariputta, Moggallana, and Ananda, four of the Buddha’s top disciples.