From Samuel Sebastian Wesley, "Wash me thoroughly from my wickedness" (and playlist, though that last one's from me, not from Wesley). I especially love how jagged the original version of the melody is when we meet it for the first time in the opening solo, and how wonderfully it is harmonized thereafter.
Wash me throughly from my wickedness, and forgive me all my sin.
For I acknowledge my faults and my sin is ever before me.
Attribution(s): "Glockenspiel Bells" by cocoparisienne (via the Visualhunt site).