Now the Greeks declare that all our affairs are controlled by the rising and setting and collision of these stars, viz., the sun and moon: for it is with these matters that astrology has to do. But we hold that we get from them signs of rain and drought, cold and heat, moisture and dryness, and of the various winds, and so forth, but no sign whatever as to our actions. For we have been created with free wills by our Creator and are masters over our actions. Indeed, if all our actions depend on the courses of the stars, all we do is done out of necessity: and necessity precludes either virtue or vice. But if we possess neither virtue nor vice, we do not deserve praise or punishment, and God, too, will turn out to be unjust, since He gives good things to some and afflicts others. Nay, He will no longer continue to guide or provide for His own creatures, if all things are carried and swept along in the grip of necessity. And the faculty of reason will be superfluous to us: for if we are not masters of any of our actions, deliberation is quite superfluous. Reason, indeed, is granted to us solely that we might take counsel, and hence all reason implies freedom of will.
And, therefore, we hold that the stars are not the causes of the things that occur, nor of the origin of things come to pass, nor of the destruction of those things that perish. They are rather signs of showers and changes of air. But, perhaps, some one may say that though they are not the causes of wars, yet they are signs of them. And, in truth, the quality of the air which is produced by sun, and moon, and stars, produces in various ways different temperaments, and habits, and dispositions. But the habits are amongst the things that we have in our own hands, for it is reason that rules, and directs, and changes them
* This excerpt is from “An Exact Exposition of the Orthodox Faith” by St. John of Damascus