Annotatio CCI
”Blessed are the undefiled in the way.” — Psalm 118:1
Hilary, prefacing on this Psalm, handed down that only three Psalms are found among the Hebrews [that are] alphabetic — that is, whose verses begin with the letters arranged according to the order of the Hebrew alphabet — namely Psalm 111, and 112, and 118.1 But the very truth of the Hebrew Psalter plainly indicates, and Jerome in the epistle to Paula Urbica confirms, that the alphabetic Psalms are five2 — namely the three aforesaid, and, besides them, [Psalms] 25 and 34. Thomas Cajetan, in the commentaries on the Psalter, to these five adds also two other Psalms arranged according to the series of the alphabet: that is, the thirty-seventh, woven with an interpolated and interrupted alphabet, and [the one] which — [Psalm] 145 — runs on with a continuous alphabet.