大方廣圓覺修多羅了義經 1.92

1.92

「善男子！云何我相？謂諸眾生心所證者。善男子！譬如有人百骸調適忽忘我身；四支絃緩，攝養乖方，微加鍼艾，則知有我。是故證取方現我體。善男子！其心乃至證於如來，畢竟了知清淨涅槃皆是我相。

"Kulaputra, what is the mark of a self? It refers to what is realized by the minds of sentient beings. Kulaputra, it is like a person whose hundred joints are in comfortable harmony and who suddenly forgets his own body; but when his four limbs are sluggish and strained through neglect of proper care, or when a moxa needle is slightly applied, he immediately knows that a self exists. Therefore, it is only through grasping at realization that the entity of the self becomes manifest. Kulaputra, even if the mind goes so far as to realize the Tathāgata and thoroughly know pure nirvāṇa, all of this is the mark of a self.