It is unclear exactly how many Passion settings Bach wrote: perhaps but not likely five, possibly three or four. Only two survive today; the second of these, the St. Matthew Passion dates from 1729. The Passions, Biblical texts set as large-scale musical works, were performed on Good Friday and told the story of Christ's Crucifixion, according to the Gospels.

The St. Matthew Passion is a work very different in character from its extant predecessor, the St. John Passion: the former is deeply devotional, introspective, and meditative in character, while the latter is more intensely dramatic, with more action in its narrative. The St. Matthew Passion is often compared with Bach's monumental Mass in B minor in terms of both scope and piety. Performed at St. Thomas' Church in Leipzig, the work sets a text by Christian Picander (who may have been the author of a hypothetical, now-lost 1725 Bach Passion). Another significant difference between the St. John and St. Matthew works lies in their respective texts: the St. John text is very short, beginning with Judas' betrayal of Christ, and focusing on Christ's trial before Pilate; the St. Matthew text, on the other hand, is very long, containing almost twice as many verses as the St. John text.

The St. Matthew Passion is also much grander musically, with its two four-part choirs and large orchestra of strings, flutes, oboes, harpsichord, and organ. Bach makes particularly poignant and varied use of his two choirs in this piece; they are heard representing the voices of different communities of believers, and also of the clamorous, derisive crowds at the Crucifixion. One celebrated aspect of the work is the way Bach uses the instrument groups to achieve various text-painting effects; a halo around Christ is suggested, for example, by the soft, sustained chords of a string ensemble, and Bach depicts the weariness of Christ on the road to Calvary with a deep pedal point. Like the St. John Passion, the St. Matthew Passion contains both Gospel text and hymn text, and both employ recitatives, arias, and choruses.

The similarities between Bach's Passions and the Catholic oratorio genre are striking. The Passions are, like the oratorio, a kind of religious opera; as in that more overtly dramatic genre, arias serve as a vehicle for lyrical expression and recitatives to advance the textual narrative. The central figure, both musically and dramatically, in the St. Matthew Passion is the Evangelist (a tenor), who narrates the story. The nature of his purely narrative, non-participatory, role is made clear through his confinement to passages of recitative; he is never afforded the opportunity for more expansive lyricism. This mode of expression falls to the other vocal soloists, who adopt the personae of those involved in the drama and give them voice.

The score is best appreciated as a whole, in which context the dramatic sweep and spiritual conviction of the work are abundantly clear. However, there are a number of notable highlights that are frequently excerpted. These include the soprano aria "Blute nur, du liebes Herz," the alto aria "Erbarme dich," which incorporates an obbligato violin, and the bass aria "Mache dich, mein Herze, rein."

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