The Rule of St. Benedict - Chapter 18. The Order Of The Psalmody

(12) Four psalms are sung each day at Vespers,
(13) starting with Psalm 109 and ending with Psalm 147,
(14) 14omitting the psalms in this series already assigned to other hours, namely, Psalms 117 through 127, psalm 133 and Psalm 142.
(15) All the remaining Psalms are said at Vespers.
(16) Since this leaves three psalms too few, the longer ones in the series should be divided: that is, Psalms 138, 143 and 144.
(17) And because Psalm 116 is short, it can be joined to Psalm 115.
(18) This is the order of psalms for Vespers; the rest is as arranged above: the reading, responsory, hymn, versicle and canticle.

(19) The same psalms — 4, 90 and 133 — are said each day at Compline.

(Feb. 24 in leap year; otherwise added to the preceding)

(20) The remaining psalms not accounted for in this arrangement for the day hours are distributed evenly at Vigils over the seven nights of the week.
(21) Longer psalms are to be divided so that twelve psalms are said each night.

(22) Above all else we urge that if anyone finds this distribution of the psalms unsatisfactory, he should arrange whatever he judges better,
(23) provided that the full complement of one hundred and fifty psalms is by all means carefully maintained every week, and that the series begins anew each Sunday at Vigils.
(24) For monks who in a week’s time say less than the full Psalter with the customary canticles betray extreme indolence and lack of devotion in their service.
(25) We read, after all, that our holy Fathers, energetic as they were, did all this in a single day. Let us hope that we, lukewarm as we are, can achieve it in a whole week.

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