Psalm 51 (Miserere mei) is the great penitiential psalm attributed to King David, and is closely associated with the Season of Lent, which begins next week. I particularly like this video because it combines images from Michelangelo's amazing frescoes in the Sistine Chapel (for which Allegri's music was specifically composed) with the text of the Psalm, in both Latin and English. This is a great way to begin preparing the heart to encounter the Pascal Mystery over the next course of the Liturgical Year.
Miserere mei Deus secundum misericordiam tuam iuxta
multitudinem miserationem tuarum dele iniquitates meas.