“Not to every one, my friends, does it belong to philosophize about God; not to every one; the Subject is not so cheap and low; and I will add, not before every audience, nor at all times, nor on all points; but on certain occasions, and before certain persons, and within certain limits. Not to all men, because it is permitted only to those who have been examined, and are passed masters in meditation, and who have been previously purified in soul and body, or at the very least are being purified. For the impure to touch the pure is, we may safely say, not safe, just as it is unsafe to fix weak eyes upon the sun’s rays.”  St. Gregory Nazianzen, Oration 27, Par. III