‘Suppose a monk were to say:
“Friends, I heard and received this from the Lord’s own lips: this is the Dhamma, this is the discipline, this is the Master’s teaching”, then, monks, you should neither approve nor disapprove his words. Then, without approving or disapproving, his words and expressions should be carefully noted and compared with the Suttas and reviewed in the light of the discipline.
If they, on such comparison and review, are found NOT to conform to the Suttas or the discipline, the conclusion must be: “Assuredly this is not the word of the Buddha, it has been wrongly understood by this monk”, and the matter is to be rejected.
But where on such comparison and review they are found to conform to the Suttas or the discipline, the conclusion must be: “Assuredly this is the word of the Buddha, it has been rightly understood by this monk.”
DN 16 Mahāparinibbāna Sutta – The Great Passing, The Buddha’s Last Days http://www.palicanon.org/