2 “Who covers with waters the upper parts thereof”. The upper parts of what? Of Heaven. What is Heaven? Figuratively only we said, the Divine Scripture. What are the upper parts of the Divine Scripture? The commandment of love, than which there is none more exalted. But wherefore is love compared to waters? Because “the love of God is shed abroad in our hearts by the Holy Spirit who is given unto us.” Whence is the Spirit Himself water? Because “Jesus stood and cried, He that believes in Me, out of his bosom shall flow rivers of living water.” Whence do we prove that it was said of the Spirit? Let the Evangelist himself declare, who follows it up, and says, “But this spoke He of the Spirit, which they were to receive, who should believe in Him.” “Who walks above the wings of the winds;” that is, above the virtues of souls. What is the virtue of a soul? Love itself. But how does He walk above it? Because the love of God toward us is greater than ours toward God.
Source: The Enarrations, or Expositions, on the Psalms (New Advent)