It may or may not be in his writings , but on one of the old Cadmon
recordings he made, after Canto XLV ("With Usura"etc.) he says, "And so you
don't continually misunderstand me, usury and interest are not the same
thing. Usury is a charge put on the use of money regardless of production or
even of the possibility of production." This is from my memory, and I may
not have it exactly verbatim.
Peace,
Charles