José Rodríguez Alvira
In measure 56 the tenor plays a motive presented before on measure 28. It is imitated by the soprano in measure 58, the alto in measure 60 and the bass in measure 62. The tenor starts in E, the soprano in A, the alto in D and the bass in G following the cycle of fifths:
This section may look as a new exposition and Bach may want us to think so by leaving the tenor almost alone in measure 56.