四分律行事鈔資持記 2.678

2.678

問中，律不犯文，不明忘故。答中。還約勤怠二心以判。事下準例可解。疏又問云：如戒緣開，何分勤惰？答：諸戒相開，並為奉者；必有惰學，隨犯根本，非是通開。

In the question: the Vinaya's non-offense text does not explain forgetting. In the answer: it is still determined with respect to the two minds of diligence and negligence. "Circumstances..." below can be understood by analogy. The Commentary also asks: "If the precept allows an exception for causes, why distinguish diligence and negligence?" Answer: "The exceptions in the various precept marks are all for those who uphold them; if there is negligent learning, one incurs the root [offense] accordingly—it is not a blanket exception."