四分比丘戒本疏 1.34

1.34

Next, the second category [of offences] is explained. The text is divided into three: first, clarifying the teaching on which it relies; second, listing the names and characteristics of the offences; third, concluding by examining whether they have been maintained. Regarding the precept on intentional emission [of semen], the Vinaya has six kinds of objects of transgression in total: first, internal form, which refers to the form of sentient beings; second, external form, which refers to insentient things; third, internal-external form, which refers to the combination of the two forms; fourth, water, which refers to moving one's body with or against the flow of water; fifth, wind, and sixth, empty space, which should be understood by analogy with water. If it occurs in a dream, it is excluded and does not incur a saṃghāvaśeṣa offence. However, sleeping with a distracted mind has five faults in the Vinaya: first, evil dreams; second, the devas do not protect one; third, the mind does not enter the Dharma; fourth, not contemplating the appearance of light; fifth, emission of semen in a dream. In the Mahīśāsaka-vinaya, sleeping with a distracted mind incurs a duṣkṛta. The Samantapāsādikā states: "If a monk sleeps while harboring mental imagery, having first made preliminary preparations, crossing his legs, clenching his hands, and sleeping with such imagery, if semen is emitted during a dream, he incurs a saṃghāvaśeṣa offence." That the precept text grants an exception is because it exempts cases where there was no preliminary preparation beforehand.