But for whatever reason, the records we have of populist preachers stirring up the masses largely seem to include genuine quotes from the Bible.
Your 14th C parish priest could actually make up anything most of the time, because the unwashed weren't allowed near the "source material."
But, in the end, if we're talking about a movement as widespread as Frank is suggesting, then it had to draw legitimacy from somewhere, and people's mindspace was "The Bible" to a large extent, as far as we know about those times.
Also, for a long time even a lot of clergymen were illiterate in latin and the introduction of the missal made it unnecessary even for priests to read the bible. When the capital development of a country becomes a by-product of the activities of a casino, the job is likely to be ill-done. — John M. Keynes