Forgive me, in advance for jumping in here so abruptly.
I’ll tell you whose authority -- his own. These inspired writings which had been cherished and venerated for 1000 or 1200 years were held in contempt by the heresiarch. Why? Because they did not suit his new doctrines and opinions. He had arrived at the heresy of private judgment – of picking and choosing religious doctrines and whenever ANY book, such as Machabees, taught a doctrine that was repugnant to his individual taste – as, for example, that “it is a holy and wholesome thought to pray for the dead that they may be loosed form sins” – well, so much the worse for the book; “THROW IT OVERBOARD” was his sentence, and overboard it went.