It was G.K. Chesterton who trenchantly reminded us that, if one was going to preach, then it was more sensible to expend one's energies on addressing the converted rather than the unconverted. It was the former, after all, that were—and even more so are—in constant danger of missing the point and sliding away from the Faith into some vague sort of syncretistic, gnostic, gobbledegook. Chesterton, as ever, was right and should you think this is just another of his tiresome paradoxes may I urge you to re-read him: his prescience concerning our present situation and, worse, where we are heading is astounding.
Simon Conway Morris