Naomi is an instance of a widow receiving back from her daughter-in-law the fruits of her own good training, and is a token that necessary support will never fail the good widow. And if her life appears sad, she is happy, since the promises of the Lord are made to her. St. Ambrose then touches upon the benefits of weeping.
33. Does the widow Naomi seem to you of small account, who supported her widowhood on the gleanings from another's harvest, and who, when heavy with age, was supported by her daughter-in-law? It is a great benefit both for the support and for the advantage of widows, that they so train their daughters-in-law as to have in them a support in full old age, and, as it were, payment for their teaching and reward for their training. For to her who has well taught and well instructed her daughter-in-law a Ruth will never be wanting who will prefer the widowed life of her mother-in-law to her father's house, and if her husband also be dead, will not leave her, will support her in need, comfort her in sorrow, and not leave her if sent away; for good instruction will never know want. So that Naomi, deprived of her husband and her two sons, having lost the offspring of her fruitfulness, lost not the reward of her pious care, for she found both a comfort in sorrow and a support in poverty.
34. You see, then, holy women, how fruitful a widow is in the offspring of virtues, and the results of her own merits, which cannot come to an end. A good widow, then, knows no want, and if she be weary through age, in extreme poverty, yet she has as a rule the reward of the training she has given. Though the nearest to herself have failed, she finds those not so near akin to cherish their mother, revere their parent, and by the trifling gifts for her support desire to gain the fruit of their own kindness, for richly are gifts to a widow repaid. She asks food and pays back treasures.
35. But she seems to spend sad days, and to pass her time in tears. And she is the more blessed in this, for by a little weeping she purchases for herself everlasting joys, and at the cost of a few moments gains eternity. To such it is well said: “Blessed are you that weep, for you shall laugh.” Who then would prefer the deceitful appearances of present joys to the pleasure of future freedom from anxiety? Does he seem to us an insignificant authority, the elect forefather of the Lord after the flesh, who ate ashes as it were bread, and mingled his drink with weeping, and by his tears at night gained for himself the joy of redemption in the morning? Whence did he gain that great joy except that he greatly wept, and, as it were, at the price of his tears obtained the grace of future glory for himself.
36. The widow has, then, this excellent recommendation, that while she mourns her husband she also weeps for the world, and the redeeming tears are ready, which shed for the dead will benefit the living. The weeping of the eyes is fitted to the sadness of the mind, it arouses pity, lessens labour, relieves grief, and preserves modesty, and she no longer seems to herself so wretched, finding comfort in tears which are the pay of love and proofs of pious memory.
Source: Concerning Widows (New Advent)