On the fifteenth, the uposatha day, the four great kings themselves wander over this world

“Bhikkhus, on the eighth of the fortnight, the ministers and assembly members of the four great kings wander over this world, thinking: ‘We hope there are many people who behave properly toward their mother and father, behave properly toward ascetics and brahmins, honor the elders of the family, observe the uposatha, keep the extra observance days, and do meritorious deeds.’ On the fourteenth of the fortnight, the sons of the four great kings wander over this world, thinking: ‘We hope there are many people who behave properly toward their mother and father, behave properly toward ascetics and brahmins, honor the elders of the family, observe the uposatha, keep the extra observance days, and do meritorious deeds.’ On the fifteenth, the uposatha day, the four great kings themselves wander over this world, thinking: ‘We hope there are many people who behave properly toward their mother and father, behave properly toward ascetics and brahmins, honor the elders of the family, observe the uposatha, keep the extra observance days, and do meritorious deeds.’“If, bhikkhus, there are few people who behave properly toward their mother and father, behave properly toward ascetics and brahmins, honor the elders of the family, observe the uposatha, keep the extra observance days, and do meritorious deeds, the four great kings report this to the Tāvatiṁsa devas when they meet and are sitting together in the Sudhamma council hall: ‘Revered sirs, there are few people who behave properly toward their mother and father, behave properly toward ascetics and brahmins, honor the elders of the family, observe the uposatha, keep the extra observance days, and do meritorious deeds.’ Then, because of this, the Tāvatiṁsa devas become displeased, saying: ‘Alas, the celestial company will decline and the company of asuras will flourish!’“But if there are many people who behave properly toward their mother and father, behave properly toward ascetics and brahmins, honor the elders of the family, observe the uposatha, keep the extra observance days, and do meritorious deeds, the four great kings report this to the Tāvatiṁsa devas when they meet and are sitting together in the Sudhamma council hall: ‘Revered sirs, there are many people who behave properly toward their mother and father, behave properly toward ascetics and brahmins, honor the elders of the family, observe the uposatha, keep the extra observance days, and do meritorious deeds.’ Then, because of this, the Tāvatiṁsa devas become elated, saying: ‘Indeed, the celestial company will flourish and the company of asuras will decline!’”The Buddha's words, Catumahārājasutta AN 3.37