Erbarme dich, mein Gott (“Have mercy Lord, My God, for the sake of my tears”) the meltingly beautiful alto aria from Bach's St. Matthew Passion, portrays Peter’s solitary heartache in the garden after he denies knowing Jesus three times. It is set in gently flowing 12/8 time, suggesting the baroque dance rhythm of the siciliano. This arrangement for string orchestra does full justice to what Yehudi Menuhin called “the most beautiful piece of music ever written for the violin."

Listen here: