descripção
The title refers 1. to the first two pitches used in the bass clarinet, a and b (= here b flat, according to German usage) from which the piece originates. ( In the viola repeated in for example measure 28 ); 2. It refers to a distichon from Der Cherubinischer Wandermann ( The Cherubian Wanderer, 1657 ) by the German Christian mystic Angelus Silesius (1624-1677), which says that for true prayer you only need two letters: a and b = ab = abba.