大乘義章 9.52

9.52

次約諸行以別其位。行有二階：一者行種、二者行德。此二之中，各有始終。就行種中，習種始習，性種終成。行德之中，解行始習，十地終成。行有此別，故分四位（此三門竟）。

Next, their stages are distinguished with reference to the various practices. Practice has two levels: first, the lineage of practice; second, the virtue of practice. Within each of these two, there is a beginning and an end. Within the lineage of practice, habituated lineage is the initial habituation, and natural lineage is the final completion. Within the virtue of practice, understanding-and-practice is the initial habituation, and the ten grounds are the final completion. Because practice has these distinctions, four stages are distinguished. (This concludes the third section.)