A quote from Cicero's Hortensius, recorded by St. Augustine in his book On the Trinity, Book XIV.
“At the end of his dialogue Hortensius, Cicero, commending this contemplative wisdom—I think the Sacred Scripture properly call it “wisdom” to distinguish it from knowledge; it is, of course, the wisdom only of man, and indeed it does not come to him from himself, but from Him of whom the rational and intellectual mind can partake so as to be truly wise—says: ‘If we consider these things day and night, and sharpen our understanding, which is the eye of the mind, and take care that it never grows dull, that is, if we live in philosophy, there is great hope, that even though our sentiments and knowledge are mortal and transitory, yet a pleasant setting rather than a painful extinction and, as it were, a rest from life will be ours when we have discharged our human offices. But if, as the ancient philosophers agreed—and indeed the greatest and by far the most illustrious among them—that we have eternal and divine souls, then we must needs think, that the more they were always in their proper course, that is, in reason and in an eagerness for investigation, and the less they mingled with and became entangled in the vices and delusion of men, so much the easier would be their ascent and return to heaven.’ And then he adds this sentence which recapitulates and concludes his treatise: ‘Therefore, to end my discourse at last, if we wish either for a peaceful extinction when we have spent out life in the pursuit of these subjects, or to migrate without delay from this home to another that is certainly much better, we must devote all our labor and care to these studies.’
I marvel here that a man of such talent promises a pleasant setting upon the discharge of their human offices to those who have spent their lives in philosophy, which makes men happy by the contemplation of the truth, if our sentiments and knowledge are mortal and transitory, just as if this which we did not love, or rather fiercely hated, were then to die and be reduced to nothing so that its setting might be pleasant for us.
He had not learned this, however, from the philosophers, upon whom he lavishes such praise; it savors rather of that New Academy where it seemed proper to doubt even the most evident truths. But, as he himself admits, he had learned from the philosophers, ‘the greatest and by far the most illustrious,’ that souls are eternal. For eternal souls are not unfittingly aroused by this exhortation, so that they may be found in their proper course when the end of this life comes, that is, in reason and in the eagerness for investigating, and they mingle less and becomes less entangled in the vices and delusions of men, in order that their return to God may be easier. But this course, which consists in the love of God and in the search for the truth, does not suffice for the miserable, that is, for all mortals who rely on this reason alone without the faith of the Mediator…” (p 165-166)
Augustine, On the Trinity, Gareth B. Matthews Edt. Stephen McKenna Translator. (2002, Cambridge University Press)