In between this biblical narration is a selection of solo arias and two ariosi recitativi (accompanied recitatives or recitativi stromentati). The latter provide a fusion of action and contemplation and are characterised by recurrent and insistent instrumental figuration of one kind or another. The solo arias are intended for in-depth reflection and contemplation of the events which have just occurred. They also comment on the action as it unfolds, and allow the opportunity for personal reaction to the events of the narrative. They are delivered by four soloists (SATB) or ‘commentators’. The words of these non-biblical movements are drawn from a number of sources. For much of Bach’s time in Leipzig he collaborated very successfully with a local poet and postal worker Christian Henrici (1700-1764), who wrote under the pseudonym of Picander. Picander wrote the non-biblical text for the St Matthew Passion and a large number of the sacred and secular cantatas, and almost certainly for the Christmas Oratorio. However, Bach had only been in Leipzig for a handful of weeks before embarking on the St John Passion, and it is likely that he was reluctant to trust the newly acquainted Picander entirely with what would have been his first major project for his new employers. Instead, Bach turned to an established Hamburg poet with whose work we know he was familiar. This poet, Barthold Heinrich Brockes (1680-1747), had published a work in 1712 called Der für die Sünden der Welt gemartete und sterbund Jesus (Jesus, tortured and dying for the sins of the world). It is essentially a passion libretto in rhyming verse. It had become very popular (30 editions were reprinted in the fifteen years from 1712) and had been set by a number of composers, including Telemann (1681-1767) in 1716 and Handel (1685-1759) in London in 1719. Bach adapted and used bits of this libretto for the St John Passion and also included a couple of extracts of work by Picander. He also used poetry by the Hamburg poet, librettist and lawyer C.H. Postel (1658-1705). There is also one aria for which it is believed Bach wrote the words himself. 

In addition, Bach inserts twelve chorales, or hymns, from the familiar Lutheran repertoire of hymnody known as Kirchenlieder. These are sung by the choir, representing the chorus of faithful believers. They would have been very familiar to the congregation and are a poetic interpolation to smooth the transition between the biblical narrative and the more emotional reflections. Their familiarity to the congregation also serves as a link between congregation and composer during the performance, and provides a contrast between music which is highly elaborate and which would have been unfamiliar to the listeners, and music which was very straightforward and familiar. Of the 77,733 Lutheran hymns known to have been published by the year 1786, Bach uses only those published in Leipzig, and therefore known to the Leipzig public. Whilst the melody and the words are by other people, the harmony is Bach’s and, as we shall see, he uses highly adventurous and colourful harmonic language very skilfully to illustrate the words. 

Bach divides the work into two parts, and a lengthy sermon would have been preached in between the two. The parts are not equal, because to have achieved this would have meant interrupting the story in the middle of the crucial action – the exchanges between Pilate and the angry mob. However, it seems that Bach had another reason for dividing up the story after the denial of Peter. We know from other works that he had a fascination with palindromic form (i.e. something which is the same when read backwards or forwards) and that fascination is exercised in the St John Passion in a sequence of movements buried in the second part of the work.