The Divine Institutes

Therefore, of all the philosophers, those who have embraced either knowledge or virtue as the chief good, have kept the way of truth, but have not arrived at perfection. For these are the two things which together make up that which is sought for. Knowledge causes us to know by what means and to what end we must attain; virtue causes us to attain to it. The one without the other is of no avail; for from knowledge arises virtue, and from virtue the chief good is produced. Therefore a happy life, which philosophers have always sought, and still do seek, has no existence either in the worship of the gods or in philosophy; and on this account they were unable to find it, because they did not seek the highest good in the highest place, but in the lowest.

For what is the highest but heaven, and God, from whom the soul has its origin? And what is the lowest but the earth, from which the body is made? Therefore, although some philosophers have assigned the chief good, not to the body, but to the soul, yet, inasmuch as they have referred it to this life, which has its ending with the body, they have gone back to the body, to which the whole of this time which is passed on earth has reference. Therefore it was not without reason that they did not attain to the highest good; for whatever looks to the body only, and is without immortality, must necessarily be the lowest.

Therefore happiness does not fall to the condition of man in that manner in which philosophers thought; but it so falls to him, not that he should then be happy, when he lives in the body, which must undoubtedly be corrupted in order to its dissolution; but then, when, the soul being freed from intercourse with the body, he lives in the spirit only. In this one thing alone can we be happy in this life, if we appear to be unhappy; if, avoiding the enticements of pleasures, and giving ourselves to the service of virtue only, we live in all labours and miseries, which are the means of exercising and strengthening virtue; if, in short, we keep to that rugged and difficult path which has been opened for us to happiness.

The chief good therefore which makes men happy cannot exist, unless it be in that religion and doctrine to which is annexed the hope of immortality.