四分比丘戒本疏 2.67

2.67

勸足食戒第三十六。文言「知他足食已」者，知僧食私食已也。若受請者，檀越食已也。此二足食竟，准前戒釋。「不作餘食法勸」者，以其作餘法已，勸而不犯故也。「以是因緣」者，惡心勸因緣也。「非餘」者，非餘不犯緣也。謂若作餘法，或病人殘、或彼比丘病等勸而不犯也。

Precept thirty-six: The precept on encouraging [someone who has eaten] sufficient food. The text says 'knowing that another has eaten sufficient food', meaning knowing that he has finished eating Saṃgha food or private food. If he received an invitation, it means having finished eating the dānapati's food. These two kinds of finishing eating to sufficiency are explained according to the preceding precept. 'Encouraging without performing the ritual of leftover food' is because if one has already performed the leftover ritual, encouraging him is not an offence. 'For this reason' refers to the condition of encouraging with bad intent. 'Not otherwise' refers to not having other non-offence conditions. That is, if the leftover ritual has been performed, or it is the leftover of a sick person, or that monk is ill, encouraging him is not an offence.