This quote is wholly irrelevant. We are talking about who gets to decide what is truly God’s Word and who get to interpret it. The Church selected the written Word and gets to interpret it. Every other contradictory interpretation is by false prophets and I am sure you know the scripture verses on that aspect.
We will have agree to disagree, for God’s Spirit moved men to prophesy, and write the words that were inspired. He would see to it that the words would be preserved. Even as Elijah thought that he was the only prophet left in Israel, God told him otherwise.
Even as king Josiah thought he was doing as God intended, he was without the complete instructions of the Law. It had been there in the temple all along, but hidden from view by carelessness of some sort. I would say that the Levites in charge of the temple were not faithfully following the Lord.
Church leadership is no different. They can say that they are representing God and his Word, yet be as wrong as Elijah, or the priestly order during Josiah’s reign.
Jesus Christ’s words in Matthew chapter 23, has a strange foreshadowing of what, IMO, is the RCC. The parallels are almost jaw dropping.