Bach's transformation into a composer primarily of sacred vocal music seems at first glance to have taken place quite suddenly. Hardly any works are datable to 1768, the year of Bach's move to Hamburg. But NV places several major vocal works in 1769, including his first Hamburg passion and an oratorio, alongside a number of instrumental works. Although the move must have taken some toll on Bach's productivity, he seems to have found life at Hamburg comfortable and congenial. He must have quickly established good working relationships with his musicians and several reliable copyists, ensuring the steady output of music not only for church and concert hall but for publication and sale. As a result, during his twenty years at Hamburg he produced vocal as well as instrumental works at a pace unprecedented for him, while successfully negotiating a hectic schedule of church and concert performances.

Viewed broadly, Bach's sacred vocal music resembles that of his father. The most important works are what we call cantatas and oratorios, most of them comprising recitatives, arias, and choral movements accompanied by instrumental ensemble; the texts mingle newly composed “madrigalesque” poetry with bible verses and chorale stanzas. Emanuel's generation was one of the last to write such works on a regular basis for church use.