References – Kd 2: The chapter on the observance day 
“I’m curious about the timeline when the Buddha established the Five Precepts for householders.” Answered by Ajahn Amaro. [Buddha/Biography] [Five Precepts] [Lay life] // [Vinaya]
Vinaya: Mahāvagga 2.1: The Buddha establishes the Uposatha observance for the Saṅgha. [Lunar observance days] [Saṅgha]
Sutta: AN 8.41: Observing the Eight Precepts on Uposatha days. [Eight Precepts]
Sutta: AN 8.39: The eight streams of merit. [Merit] [Three Refuges] [Generosity]
Follow-up: “Did the ritual of requesting the Five Precepts originate in the time of the Buddha?” Answered by Ajahn Amaro and Ajahn Pasanno. [Ceremony/ritual] [Culture/Thailand] [Tipiṭaka]
Readings from The Island [2025], Session 50, Excerpt 11
“Why did Jīvaka ask whether a virtuous lay follower is practicing for themselves or others (AN 8.26)?” Answered by Ajahn Pasanno. [Great disciples] [Lay life] [Virtue] [Compassion] [Buddhist identity] // [Culture/India] [Lunar observance days] [Teaching Dhamma]
Vinaya: Mahāvagga 2.1.1: Origin of Lunar Observance Days.