My Scottish correspondent commented some posts below, in regard to the Breviary: "Humbert of Romans said that the 'greater part of our Penance consists in the daily recitation of the Office'. Notice he says part, so it alone is not all our penance; besides, it is not only penance - it can also be a joy."
Of ourselves as sinful men (and I speak first of myself), all we deserve is penance; but the Lord deigns to console us also, such is His mercy.
I fully agree with Humbert's opinion: that's why, despite its sometimes fatiguing length, I do make it a rule to say some form of the Divine Office every day: for well over a decade, it was the modern Liturgy of the Hours; then more recently I've more and more used the 1962 Breviary; and for the past seven weeks, I have been reciting the Little Office of Our Lady (whose relative brevity turns out to fit more easily with my work commitments), to the point that much of it is becoming second nature to me.
Why the Office? Well, fundamentally it is singing the praise of God in His own words: and since this shall be our entire occupation hereafter (if we avoid hell), it is fitting to make some preparation for this in the present. Prayer is not about changing God's will, but about conforming our will to His: praying the Scriptures is of signal use in this. Add to this the holy prayers of the Church, and the remembrance of notable saints as models for us, yes, and intercessors...
Being sick at home and away from work, these last three days I've managed the full Office again, and it has been both a penance, and a joy. While I have a great and even-deeper love for the Office of the Blessed Virgin, which is hard to tear myself away from, the sombre majesty of the ferial Office in particular is important, part of the innate genius of the Roman Rite.
Matins of Fridays - with the very long Psalm 77 (in six parts), then Psalms 78, 80 and the enjoyable 82 (confounding Israel's enemies) - is penance indeed! So, too, is Friday None, as I've blogged about before: Psalm 88 is prodigiously long. Lauds is, also, with a particularly long canticle from Isaias xlv, 15-26, Vere tu es Deus absconditus, to be prayed: an important text, but fatiguing.
But there are joys, too - the Passion Psalm, Psalm 21, at Prime; several familiar Psalms at Lauds (98 and 142, both splendid, plus 84 and 147, used at Prime and Vespers of Our Lady); and the blessedly short Terce and Sext (Psalms 79, 81, 83 and 86, all beaut psalms, the last used at Matins of the Virgin) to make up for the length of the rest of the Hours.
(Wednesday, Thursday, and to-day I've prayed the Hours from Matins to None en bloc in the mid-afternoon, after 3 pm, the hour of Christ's Death on Calvary. Penance, penance...)