《佛说四十二章经》
佛问沙门:人命在几间?对曰:数日间。佛言:子未知道。
复问一沙门:人命在几间?对曰:饭食间。佛言:子未知道。
复问一沙门:人命在几间?对曰:呼吸间。
佛言:善哉,子知道矣!
The Buddha asked a third monk,
"How do you measure the length of a man's life?"
The monk answered, "By the breath."
The Buddha said, "Very well, you know the Way."《the Sutra of Forty-two Chapters》