俱舍論疏 14.119

14.119

論「具足受八支至近住不成」，釋具支闕不成也。《正理論》云「具受八支方成近住，隨有所闕近住不成，諸遠離支互相屬故。由是四種離殺等支，於一身中可俱時起，以諸遠離相繫屬中或少或多相差別故。」

The commentary states: "Completely receiving the eight factors [...] upavāsa is not accomplished", which explains that if any factor is lacking, it is not accomplished. The Nyāyānusāra states: "Only by completely receiving the eight factors is upavāsa accomplished; whenever there is any deficiency, upavāsa is not accomplished, because the various abstention-factors are mutually dependent. Hence the four factors—abstaining from killing and so forth—can arise together in a single body, because among these mutually dependent abstentions there are distinctions of fewer or more."