成唯識論述記 10.226

10.226

述曰：今以理答。住、滿地中時既淹久，謂二僧祇，理更應斷，若不更斷爾者，地三時道既無三品，應無別故。

The Commentary states: Now answering through reasoning: because the dwelling and culminating [phases] of the grounds last for a long time, namely two asaṃkhyeya [kalpas], in principle one should sever further; if one did not sever further, then since the paths of the three periods of a ground would not have three grades, they would not be distinct.