律戒本疏 1.42

1.42

二十一長鉢　鉢以盛食得一便足。六群比丘多畜無節。因是結戒。不得長畜。取時突。過十日捨墮。有三種上鉢。他飯一鉢他羹菓等可食物半羹。中者求上。下者下中。大過上小過下非鉢。不應受持也。

Twenty-one: Extra alms-bowls. A bowl is used for holding food; having one is sufficient. The ṣaḍvargika monks accumulated many without moderation. On account of this, [the Buddha] formulated the precept: one must not keep an extra bowl. At the time of taking it, one incurs a duṣkṛta; if it exceeds ten days, it is a forfeiture and pāyattika. There are three kinds: a superior bowl holds one bowlful of another's rice, and half a bowl of another's soup, fruit, and other edible foods; a medium one seeks between the superior and inferior; an inferior one is below the medium. One larger than the superior or smaller than the inferior is not a [proper] bowl and should not be received and kept.