Lewis took on the role of an apologist for the Christian faith. In an essay entitled “Christian Apologetics,” he honed in on one of the big problems Christians have when trying to explain the truth of Christianity. It’s not a problem with the message itself, but with the hearers of the message:
One of the great difficulties is to keep before the audience’s mind the question of Truth. They always think you are recommending Christianity not because it is true but because it is good. And in the discussion they will at every moment try to escape from the issue “True—or False” into stuff about a good society, or morals . . . or anything whatever.
You have to keep forcing them back, and again back, to the real point. Only thus will you be able to undermine . . . their belief that a certain amount of “religion” is desirable but one mustn’t carry it too far. One must keep on pointing out that Christianity is a statement which, if false, is of no importance, and if true, of infinite importance. The one thing it cannot be is moderately important.