die Tropfen meiner Zähren

"Do you have any hobbies?"
"Listening to music."
"What kind of music?"
"I like Bach."
"Anything in particular?"
"BWV 846 to 893."
Tengo mulled that one over. "The Well-Tempered Clavier, Books I and II."
"Yes."
"Why did you answer with the BWV numbers?"
"They're easier to remember."
The Well-Tempered Clavier was truly heavenly music for mathematicians. It was composed of prelude and fugue pairs in major and minor keys using all twelve tones of the scale, twenty-four pieces per book, forty-eight pieces in all, comprising a perfect cycle.
"How about other works?" Tengo asked.
"BWV 244."
Tengo could not immediately recall which work of Bach's had a BWV number of 244.
Fuka-Eri began to sing.

Buß’ und Reu’
Knirscht das Sündenherz entzwei
Daß die Tropfen meiner Zähren
Angenehme Spezerei
Treuer Jesu, dir gebären
Knirscht das Sündenherz entzwei
Knirscht das Sündenherz entzwei
Buß’ und Reu’ Buß’ und Reu’
Knirscht das Sündenherz entzwei
Buß’ und Reu’
Buß’ und Reu’
Knirscht das Sündenherz entzwei
Buß’ und Reu’
Buß’ und Reu’

Tengo was momentarily dumbstruck. Her singing was not exactly on key, but her German pronunciation was amazingly clear and precise. 　
“‘St. Matthew Passion,’ ” Tengo said. “You know it by heart.” 　
“No I don’t,” the girl said. 　
Tengo wanted to say something, but the words would not come to him. All he could do was look down at his notes and move on to the next question.
--Haruki Murakami, 1Q84

Translation of the German text:

Guilt and pain
Break the sinful heart in twain,
So the teardrops of my weeping
A most soothing precious balm,
Jesus, thee doth offer. (Minnesota Public Radio)