In the Buddha’s time, people of many faiths were already keeping a sabbath on the Full and New Moons, called observing the Uposatha. When they requested that the Buddha also lay out an observance for this holy day, the Buddha described the practice of taking the 8 Precepts for a day and a night. Doing so, he said, was to live a day and a night like the arahants – the enlightened beings.