Great answer from Gregory Wolfe at Sojourn:
Bobby Gilles: How would you respond to Christians who say, “Why would I read or watch anything that isn’t true?” or “Why read anything but the Bible?”
Gregory Wolfe: You want me to answer these questions in how many words? If the Bible is a closed feedback loop – read me but read nothing else – then sign me up for another religion. I think it’s saying the opposite: read me faithfully and you will be equipped to read everything. If scripture doesn’t send you out into the world with curiosity and compassion, then it’s not from God. Also, since scripture itself warns us about reading the “letter” while missing the “spirit,” we have a perfect rationale for the truth that can be found in “fiction.” Great fiction enables us to encounter the spirit (which is truth) through artfully arranged letters.