妙法蓮華經玄贊 4.100

4.100

本生相者，《顯揚論》云：「謂於是中宣說世尊在過去世，彼彼方所若死若生，行菩薩行、行難行行，是名本生。說佛為菩薩時若身若行，皆本生故。」《涅槃經》中唯說菩薩往身，不說菩薩往行，作鹿作熊作麞作菟，乃至廣說作金翅鳥等。

As for the characteristic of jātakas, the *Xianyang-lun* says: 'It refers to proclaiming herein the Bhagavat in past lifetimes, in various places, dying or being born, practicing the bodhisattva conduct, practicing difficult practices—this is called jātaka. Because stating the Buddha when he was a bodhisattva, whether his bodies or his practices, all are jātaka.' In the *Nirvāṇa-sūtra*, it speaks only of the bodhisattva's past bodies, not speaking of the bodhisattva's past practices: acting as a deer, a bear, a roe deer, a hare, down to extensively speaking of acting as a garuḍa, etc.