妙法蓮華經玄義 7.119

7.119

九、本壽命妙者，上因妙中以智慧為命；此則非長、非短。由非長、非短之慧命，能為長、短，此中正明長、短壽命。經處處自說名字不同，年紀大小。年紀者，是壽命也。大小者，長短也。經中間處處年紀大小者，約迹而懸指本也。迹不同者：三藏佛父母生身，八十二盡，身灰智滅，畢竟不生；通教佛誓願之身，化緣若訖，亦歸灰斷，滅已不生。此兩佛但齊業齊緣，不得非長、非短之慧命，不能作長、作短，大、小之壽命也。別教登地破無明，得如來一身無量身，一身湛然安住，無量身百界作佛，亦示九界身，得論年紀大、小。大即大乘常壽；小即小乘無常之壽也。圓教登住時，亦如是。此等皆因中菩薩，非常、非無常，能作常無常、大小之壽，況後心乎！況妙覺乎！

Ninth, concerning the wondrous lifespan of the original source: in the section on the wondrous cause above, wisdom was taken as life; here it is neither long nor short. By means of this wisdom-life that is neither long nor short, one is able to manifest long and short [lifespans]; here we specifically clarify long and short lifespans. The sūtras here and there themselves speak of differing names and of greater or lesser ages. 'Age' refers to lifespan; 'greater and lesser' refers to long and short. The greater and lesser ages mentioned everywhere throughout the sūtras refer implicitly to the original source in terms of the traces. As for the differences among traces: the physical body born of parents of the buddha of the tripiṭaka teaching comes to an end at eighty; with the body reduced to ashes and consciousness extinguished, he is ultimately not reborn. When the circumstances for conversion have ended for the vow-body of the buddha of the shared teaching, it likewise returns to ash and extinction, and once extinguished is not reborn. These two buddhas merely conform to karma and conform to conditions; not attaining the wisdom-life that is neither long nor short, they cannot manifest long or short, great or small lifespans. In the distinctive teaching, upon ascending to the stages [of the ten bhūmis] and destroying ignorance, one attains the single body and immeasurable bodies of the Tathāgata; the single body abides serenely, while the immeasurable bodies manifest as buddhas in hundreds of realms and also display the bodies of the nine realms, so that greater and lesser ages can be discussed. The 'great' is the eternal lifespan of the Great Vehicle; the 'small' is the impermanent lifespan of the Small Vehicle. The same applies when ascending to the stages of abiding in the perfect teaching. These are all bodhisattvas in the causal stages who, being neither eternal nor non-eternal, are able to manifest eternal and non-eternal, great and small lifespans—how much more so the final mind [of the path]! How much more so marvelous awakening!