四分戒本疏卷第一．第二．第三 3.37

3.37

重屋上坐脫脚床戒第十八　制意者。凡事宜審。危險須慎。重屋薄覆脫脚之床。放身坐臥。容有墜傷。於下人惱處不輕。是故聖制　別緣有四。一重屋。二薄屋。三脫脚床。四放身坐臥。已下正明戒本。此戒因同房重屋比丘起過。制此戒。

Precept 18: Sitting on a bed with detachable legs in an upper storey. / The intention behind its enactment: In all matters, one should exercise caution; where there is danger, one must be prudent. On an upper storey with thin roofing, if one throws oneself down to sit or lie on a bed with detachable legs, there is a risk of falling through and causing injury; the harm to those below would not be light. Therefore, the Sage enacted [this precept]. / There are four specific conditions: first, an upper storey; second, a thin roof; third, a bed with detachable legs; fourth, throwing oneself down to sit or lie down. Below, the text of the precept is directly clarified. This precept was enacted because a bhikṣu sharing an upper-storey room incurred a fault.