雜譬喻經 1.32

1.32

In a foreign country there was a dwelling place. Among the assembly there was a man of the Way who defecated on the pure ground of the monastic saṃgha. There was another man of the Way who was prone to great anger, and he licked it with his tongue to display it to the assembly. Although he wished to make manifest the other person's offence, he did not realise that he was defiling his own mouth. This illustrates that when people are fond of speaking of others' evil, it is like this: they only know to expose another's fault, but do not realise that they are destroying their own conduct.