6 “Your mercy, O Lord, is in the heavens, and Your truth reaches even unto the clouds”. I know not what Mercy of Him he means, which is in the heavens. For the Mercy of the Lord is also in the earth. You have it written, “The earth is full of the Mercy of the Lord.” Of what Mercy then speaks He, when He says, “Your Mercy, O Lord, is in the heavens”? The gifts of God are partly temporal and earthly, partly eternal and heavenly. Whoso for this worships God, that he may receive those temporal and earthly goods, which are open to all, is still as it were like the brutes: he enjoys indeed the Mercy of God, but not that which is excepted, which shall not be given, save only to the righteous, to the holy, to the good.
What are the gifts which abound to all? “He makes His sun to rise on the evil and on the good, and sends rain on the just and on the unjust.” Who has not this Mercy of God, first that he has being, that he is distinguished from the brutes, that he is a rational animal, so as to understand God; secondly, that he enjoys this light, this air, rain, fruits, diversity of seasons, and all the earthly comforts, health of body, the affection of friends, the safety of his family? All these are good, and they are God's gifts....
Source: The Enarrations, or Expositions, on the Psalms (New Advent)