This is a charade - multiple separate components are joined together in sequence to build the final answer.
Break this into parts: 'English' gives you one letter, 'bishop' represents an abbreviation (think of a formal title), 'a' stays as is, and 'set of holy books' becomes a two-letter abbreviation. Put them all together in order.
Answer: ERRANT | E (English) + RR (Right Reverend, meaning bishop) + A + NT (New Testament, the set of holy books) = ERRANT (misbehaving)