Just rediscovered this wonderfully acerbic response from Dorothy L. Sayers (mystery-suspense author and theological writer) to an agnostic scientist. The poor man was asking her to write a letter to his organization explaining the Christian faith. I don't know if he got what he deserved but her reply is just remarkable.
"Why do you want a letter from me? Why don't you take the trouble to find out for yourselves what Christianity is? You take time to learn technical terms about electricity. Why don't you do as much for theology? Why do you never read the great writings on the subject, but take your information from the secular 'experts' who have picked it up as inaccurately as you? Why don't you learn the facts in this field as honestly as your own field? Why do you accept mildewed old heresies as the language of the church, when any handbook on church history will tell you where they came from? Why do you balk at the doctrine of the Trinity - God the three in One - yet meekly acquiesce when Einstein tells you E=mc2? What makes you suppose that the expression "God ordains" is narrow and bigoted, while your own expression, "Science demands" is taken as an objective statement of fact?
You would be ashamed to know as little about internal combustion as you know about Christian beliefs. I admit, you can practice Christianity without knowing much theology, just as you can drive a car without knowing much about internal combustion. But when something breaks down in the car, you go humbly to the man who understands the works; whereas if something goes wrong with religion, you merely throw the works away and tell the theologian he is a liar.
Why do you want a letter from me telling you about God? You will never bother to check on it or find out whether I'm giving you personal opinions or Christian doctrines. Don't bother. Go away and do some work and let me get on with mine."