Corpus of Latin Ecclesiastical Writers, Vol. LXII: Ambrose's Exposition of Psalm 118

1. Although the prophet David spoke as if with the sound of a trumpet, the great teacher of morals declares in the supreme grace of this psalm how much ethics excels in him. Since all moral doctrine is sweet, it delights the ears and soothes the mind especially with the sweetness of its song 5 and the pleasantness of its chanting. 2 Deservedly, in many places of the moral psalms, he scattered the sentences like the lights of stars which shine and stand out. Truly, he placed the one hundred and eighteenth psalm in the progress of the book like a sun of full light burning in the midday heat, so that 10 neither the half-full beginnings of the morning sunrise nor the somewhat elderly decline of the evening sunset might take anything away from the clarity of its perfect splendor. 3 He arranged it through the individual letters of the Hebrews, so that just as the minds of little children grow accustomed to the first elements of letters to acquire the use of learning, so also we might learn the use of living through elements of this kind.
15 2. He assigned eight verses to each individual letter, so that he might teach both unity—for unity restrains and rules all things, to which all things are subject—and the cleansing of legitimate
17 sanctification.