15 “He has not dealt with us according to our sins”. Thanks unto God, because He has vouchsafed this. We have not received what we were deserving of: “He has not dealt with us according to our sins, nor rewarded us according to our wickednesses.” “For as the height of heaven above the earth, so has the Lord confirmed His mercy toward them that fear Him”. Observe the heaven: everywhere on every side it covers the earth, nor is there any part of the earth not covered by the heaven. Men sin beneath heaven: they do all evil deeds beneath the heaven; yet they are covered by the heaven. Thence is light for the eyes, thence air, thence breath, thence rain upon the earth for the sake of its fruits, thence all mercy from heaven. Take away the aid of heaven from the earth: it will fail at once. As then the protection of heaven abides upon the earth, so does the Lord's protection abide upon them that fear Him. You fear God; His protection is above you. But perhaps you are scourged, and conceive that God has forsaken you. God has forsaken you, if the protection of heaven has forsaken the earth.
Source: The Enarrations, or Expositions, on the Psalms (New Advent)