畜長鉢戒二十一
Twenty-first Precept on Keeping an Extra Bowl
所以過十日者。然物變無恒。容有失脫。資身要用事不可廢。施時不取後須難得。所以開限十日作法。而畜過則致犯。餘如長衣戒者。同彼有忘等諸緣亦開無犯。內外資身別去。鉢唯內資衣則外要。
Therefore, the ten-day limit exists because circumstances are never fixed, and losses or oversights may occur. Since these essentials for daily life cannot be dispensed with, if you do not obtain them at the time of offering, it may be hard to come by later—hence the allowance of a ten-day period for the proper procedure. But keeping them beyond that creates a fault. Other matters, as in the Robe Allowance Rule, are the same: if there are forgetfulness or other conditions, it is also exempt from offense. The inner and outer supports for the body differ—the bowl is for inner sustenance, while the robe is for outer necessity.