You should know for this excerpt that Gaetulia was an area in the northwest of interior Africa (modern-day Morocco) inhabited by nomadic tribes; it ran from the southern slopes of the Atlas Mountains to the oases in the northern part of the Sahara.
“Fire, hail, snow, stormy winds that do his word” (Ps 148:8). Why does the Psalmist add: “Which do his word”? There are many foolish people who are unable to contemplate and to discern creatures in their places and their order, moving by God’s wish and command. They think that God governs all superior things but that he despises inferior things, discards them, deserts them; he doesn’t care for them, doesn’t govern them, doesn’t rule them. Chance determines how they move and where they move. They sometimes say to themselves..: “If it’s God who rains, would he rain upon the sea? What kind of providence is that? Gaetulia goes thirsty, and it pours on the sea.” They think they’re clever, but to them we could reply: “Even Gaetulia thirsts, but you don’t! You should have said to God, “My soul is toward you like a dry land, without water” (Ps 142:6), which is said openly in another place: “My soul has sought you, my flesh, too, in so many ways!” (Ps 62:2). And in the Gospel the Lord says: “Blessed are they who hunger and thirst for righteousness, for they shall be filled” (Mt 5:6) Anyone who argues that way thinks he’s so educated he doesn’t need to learn, and that’s why he’s not thirsty. If he were thirsty, he’d want to learn and he’d find that everything on earth happens by God’s providence, and he would marvel at the well-ordered parts even of a flea. Think of it, beloved. Who arranged the parts of a flea and a gnat so that they have their order, have their life, have their movement. Think of a small insect, the tiniest you desire. If you consider the order of its parts and the life that animates it, how it flees death, loves life, desires pleasure, avoids trouble, makes use of its senses, thrives in its own way. Who gave the flea a sting to draw blood? How fine is the tube by which it sucks it in! Who arranged all this? Who made all this? You’re afraid of these tiny things; praise him who is great. (EnPs 148, 10; PL 37, 1943-1944)