Factus est Dominus protector meus, et eduxit me in latitudinem: salvum me fecit, quoniam voluit me.
“The Lord became my protector, and he guided me into the open. He saved me, because he wanted me.” (Ps 18(17):19–20)
When you take only the final notes of each of the syllables pro-tec-tor me-us, you get a very simple recitation mainly on the pitch la (a). All the other notes give these syllables a beautiful tremble. My God is a protector, he is a guardian: Saying this loud is somehow thrilling. All these trembling notes are the Gregorian way to say “Wow!”