| O Ewigkeit, du Donnerwort | |
|---|---|
BWV 20 | |
| Chorale cantata by J. S. Bach | |
 Nikolaikirche, c. 1850 | |
| Occasion | First Sunday after Trinity |
| Chorale | "O Ewigkeit, du Donnerwort" by Johann Rist |
| Performed | 11 June 1724: Leipzig |
| Movements | 11 in two parts (7, 4) |
| Vocal |
|
| Instrumental |
|
Johann Sebastian Bach composed the church cantata O Ewigkeit, du Donnerwort (O eternity, you word of thunder),[1] BWV 20, in Leipzig for the first Sunday after Trinity, which fell on 11 June in 1724. Bach composed it when beginning his second year as Thomaskantor in Leipzig. It is the first cantata he composed for his second annual cycle which was planned to contain chorale cantatas, each based on a Lutheran hymn. The cantata is focused on Johann Rist's 1642 hymn "O Ewigkeit, du Donnerwort", with a chorale melody by Johann Schop. The topic of death and eternity matches the Gospel for the Sunday, the parable of the Rich man and Lazarus.
As usual for Bach's chorale cantatas to come in the cycle, selected hymn stanzas were retained while the others were paraphrased by a contemporary poet who transformed their ideas into a sequence of alternating recitatives and arias. For this cantata, the first stanza was used unchanged, and two more stanzas to conclude the cantata's two parts. The first part was performed before the sermon, the second part after the sermon. The first part is in seven movements, and the second part is in four movements.
Bach scored the cantata for three vocal soloists, a four-part choir and a Baroque instrumental ensemble of two tromba da tirarsi, three oboes, two violins, viola and basso continuo. Schop's chorale melody appears in the movements with the original text, the opening chorale fantasia and the (identical) four-part harmonisation closing the cantata's two parts. All instruments play in the opening chorale fantasia, in which the soprano sings the hymn tune as a cantus firmus. It is written in the style of a solemn French Overture, opening both the cantata and the second cantata cycle.