Augustine, Saint, De Genesi Ad Litteram

Ideoque fatendum est, quando ab istis uera dicuntur, instinctu quodam occultissimo dici, quem nescientes humanae mentes patiuntur. quod cum ad decipiendos homines fit, spirituum seductorum operatio est: quibus quaedam uera de temporalibus rebus nosse permittitur partim subtilioris sensus acumine, quia corporibus subtilioribus uigent, partim experientia callidiore propter tam magnam longitudinem uitae, partim sanctis angelis, quod ipsi ab omnipotente deo discunt, etiam iussu eius sibi reuelantibus, qui merita humana occultissimae iustitiae sinceritate distribuit. aliquando autem idem nefandi spiritus etiam quae ipsi facturi sunt uelut diuinando praedicunt. quapropter bono christiano siue mathematici siue quilibet inpie diuinantium, maxime dicentes uera, cauendi sunt, ne consortio daemoniorum animam deceptam pacto quodam societatis inretiant.

And therefore it must be admitted that, when true things are said by these people, they are said by some most hidden prompting, which human minds undergo without knowing it. When this is done to deceive people, it is the work of seducing spirits, who are permitted to know certain true things about temporal matters: partly by the sharpness of a finer sense, because they are strong with finer bodies; partly by a more cunning experience, owing to so great a length of life; partly because holy angels reveal to them what they themselves learn from almighty God, even at the command of him who distributes human deserts with the integrity of a most hidden justice. Sometimes, too, these same wicked spirits foretell, as if by divination, even what they themselves are going to do. Therefore a good Christian must beware of mathematici [astrologers], or of any who practise impious divination, especially when they say true things, lest they ensnare a deceived soul in fellowship with demons by some pact of partnership.