Those things which are generally looked on as good are mostly hindrances to a blessed life, and those which are looked on as evil are the materials out of which virtues grow. What belongs to blessedness is shown by other examples.
16. But those things which seem to be good, as riches, abundance, joy without pain, are a hindrance to the fruits of blessedness, as is clearly stated in the Lord's own words, when He said: “Woe to you rich, for you have received your consolation! Woe unto you that are full, for you shall hunger, and to those who laugh, for they shall mourn!” So, then, corporal or external good things are not only no assistance to attaining a blessed life, but are even a hindrance to it.
17. Wherefore Naboth was blessed, even though he was stoned by the rich; weak and poor, as opposed to the royal resources, he was rich in his aim and his religion; so rich, indeed, that he would not exchange the inheritance of the vineyard received from his father for the king's money; and on this account was he perfect, for he defended the rights of his forefathers with his own blood. Thus, also, Ahab was wretched on his own showing, for he caused the poor man to be put to death, so as to take possession of his vineyard himself.
18. It is quite certain that virtue is the only and the highest good; that it alone richly abounds in the fruit of a blessed life; that a blessed life, by means of which eternal life is won, does not depend on external or corporal benefits, but on virtue only. A blessed life is the fruit of the present, and eternal life is the hope of the future.
19. Some, however, there are who think a blessed life is impossible in this body, weak and fragile as it is. For in it one must suffer pain and grief, one must weep, one must be ill. So I could also say that a blessed life rests on bodily rejoicing, but not on the heights of wisdom, on the sweetness of conscience, or on the loftiness of virtue. It is not a blessed thing to be in the midst of suffering; but it is blessed to be victorious over it, and not to be cowed by the power of temporal pain.
20. Suppose that things come which are accounted terrible as regards the grief they cause, such as blindness, exile, hunger, violation of a daughter, loss of children. Who will deny that Isaac was blessed, who did not see in his old age, and yet gave blessings with his benediction? Was not Jacob blessed who, leaving his father's house, endured exile as a shepherd for pay, and mourned for the violated chastity of his daughter, and suffered hunger? Were they not blessed on whose good faith God received witness, as it is written: “The God of Abraham, the God of Isaac, and the God of Jacob”? A wretched thing is slavery, but Joseph was not wretched; nay, clearly he was blessed, when he while in slavery checked the lusts of his mistress. What shall I say of holy David who bewailed the death of three sons, and, what was even worse than this, his daughter's incestuous connection? How could he be unblessed from whom the Author of blessedness Himself sprung, Who has made many blessed? For: “Blessed are they who have not seen yet have believed.” All these felt their own weakness, but they bravely prevailed over it. What can we think of as more wretched than holy Job, either in the burning of his house, or the instantaneous death of his ten sons, or his bodily pains? Was he less blessed than if he had not endured those things whereby he really showed himself approved?
21. True it is that in these sufferings there is something bitter, and that strength of mind cannot hide this pain. I should not deny that the sea is deep because inshore it is shallow, nor that the sky is clear because sometimes it is covered with clouds, nor that the earth is fruitful because in some places there is but barren ground, nor that the crops are rich and full because they sometimes have wild oats mingled with them. So, too, count it as true that the harvest of a happy conscience may be mingled with some bitter feelings of grief. In the sheaves of the whole of a blessed life, if by chance any misfortune or bitterness has crept in, is it not as though the wild oats were hidden, or as though the bitterness of the tares was concealed by the sweet scent of the grain? But let us now proceed again with our subject.
Source: On the Duties of the Clergy (New Advent)