[134] On one occasion the Blessed One was dwelling at Vesālī, in the Great Wood, in the hall with the peaked roof. Then Vāseṭṭha the lay follower approached the Blessed One; having approached and paid homage to the Blessed One, he sat down to one side. As Vāseṭṭha the lay follower was sitting to one side, the Blessed One said this to him: "Vāseṭṭha, the uposatha (uposatha), when observed complete in eight factors, is of great fruit … blameless, they go to the heavenly state."
When this was said, Vāseṭṭha the lay follower said to the Blessed One: "Bhante, if my dear relatives and kin were to observe the uposatha complete in eight factors, it would be for the welfare and happiness of my dear relatives and kin for a long time. If all khattiyas, Bhante, were to observe the uposatha complete in eight factors, it would be for the welfare and happiness of all khattiyas for a long time. If all brahmins, Bhante, … vessas … suddas were to observe the uposatha complete in eight factors, it would be for the welfare and happiness of all suddas for a long time."
"If, Vāseṭṭha, all khattiyas were to observe the uposatha complete in eight factors, it would be for the welfare and happiness of all khattiyas for a long time. If, Vāseṭṭha, all brahmins … vessas … suddas were to observe the uposatha complete in eight factors, it would be for the welfare and happiness of all suddas for a long time. If, Vāseṭṭha, the world with its devas, with its Māra, with its Brahmā, this generation with its ascetics and brahmins, with its devas and humans, were to observe the uposatha complete in eight factors, it would be for the welfare and happiness for a long time of the world with its devas, with its Māra, with its Brahmā, of this generation with its ascetics and brahmins, with its devas and humans. And if, Vāseṭṭha, these great sāl trees were to observe the uposatha complete in eight factors, it would be for the welfare and happiness of these great sāl trees for a long time—if they could think—how much more, then, for one who has become a human being?"
English translation from the Pali (Siam Raṭṭha edition) — under review, not for citation.