四分律比丘含注戒本 2.113

2.113

If one does not accept the senior's instruction, and resents and reviles him, it is a duṣkṛta. Cases of non-offense: if there is a real matter, and fearing later regret, one speaks to urge him to reveal it in accordance with the Dharma, and then says "He has favoritism" and so forth; if speaking in jest or by mistake—in all these there is no offense.