Does anyone know the source of this teaching:
Free From Assertions Regarding Philosophical Views,
Free from Mental Fabrication in Meditation,
Free from Accepting or Rejecting Regarding Conduct,
Free from Hopes and Fears Concerning the Result.
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You may find such expressions all over the exclamations of Arahats and the Buddha, like in Magandiya Sutta and mostly in the Theragata, Therigata. In regard of "Mental Fabrication in Meditation", such is found in the description of the Jhanas. It's not about a Yana, as suggested in the discussion of the OP, but the result of Mahayana (taking the transcendent Eightfold Path "without effluents, transcendent, a factor of the path", the path of the Noble ones, as Maha). The last sentence is the most dangerous for beings, misunderstand it (or thing that such can be imitated), but it has its cause, since no more kamma is done being an Arahat, and of cause no reason for harming actions arises.
(Note: this answer has not been given with the agreement to be means of trade or the purpose of trade and keep people trapped and bound. How you handle it lies in your sphere, but does not excuse the deed here either.)