大乘百法明門論開宗義決 1.41

1.41

亦非年月定判後先者。真諦三藏亦立三時與此不殊而不取者。由約年月定判後先。說佛成道十二年來所說小乘名第一時。從十二年後至三十七年說般若等為第二時。三十八年至涅槃來所說中道名第三時。若作此說。花嚴經等成道初說。豈即初時。故約年月定判後先。有此過失而不取也。

Regarding "nor is it that temporal sequence is definitively determined by months and years": Tripiṭaka Master Paramārtha also established three periods not different from this, yet [his view] is not adopted. This is because he definitively determined earlier and later according to months and years, saying that what the Buddha taught during the twelve years after attaining awakening was Hīnayāna, called the first period; from after twelve years up to thirty-seven years, the teaching of Prajñā and so forth was the second period; and from thirty-eight years up to nirvāṇa, the teaching of the Middle Way was the third period. If one makes this statement, then since the Avataṃsaka-sūtra and others were taught at the beginning of awakening, could they belong to the first period? Therefore, definitively determining earlier and later according to months and years entails this fault, and thus is not adopted.