Johann Sebastian Bach: Erbarme Dich, mein Gott

Here for Easter is Kathleen Ferrier singing (in English translation) an aria from Bach's St Matthew Passion.

As Wikipedia says, it is widely regarded as one of the masterpieces of classical sacred music. Heartbreakingly, Wikipedia also says: "Although Bach wrote four (or five) settings of the Passions only two have survived; the other is the St John Passion."

For more on Bach and his music watch last night's BBC2 documentary Bach: A Passionate Life (available for another six days).