77 And since in speaking of holy Elijah's dwelling in the desert, we have passed by without notice the names of places which were not given without a purpose, it seems well to go back to what they signify. Elijah was sent to the brook Cherith, and there the ravens nourished him, bringing him bread in the morning, for it “strengthens man's heart.” For how should the prophet be nourished except by mystical food? At evening flesh was supplied. Understand what you read, for Cherith means “understanding,” Horeb signifies “heart” or “as a heart,” Beersheba also is interpreted “the well of the seventh,” or “of the oath.”
Source: Letters (New Advent)