四分律比丘含注戒本 1.226

1.226

佛在羅閱祇。慈地比丘見羊行婬，便言：「此羝羊者，沓婆也；其母羊者，即慈地尼。」便語比丘：「我今親見，非前無根。」比丘詰問，便自臣伏。舉過白佛，而制此戒。

The Buddha was in Rājagṛha. The bhikṣu Mettiya saw goats mating and said: "This ram is Dabba; that ewe is the bhikṣuṇī Mettiyā." He then said to the bhikṣus: "I have now seen it with my own eyes; it is not groundless like before." When the bhikṣus cross-examined him, he submitted himself. They brought up the fault and informed the Buddha, who laid down this precept.