O Ewigkeit, du Donnerwort (O eternity, you word of thunder), BWV 20, is a church cantata by Johann Sebastian Bach. He composed it in Leipzig for the first Sunday after Trinity Sunday and first performed it on 11 June 1724. It is the first cantata he composed for his chorale cantata cycle, the second annual cycle he started in Leipzig. The cantata is based on Johann Rist's hymn "O Ewigkeit, du Donnerwort" (1642), with a chorale melody by Johann Schop.

Librettist Anonymous ((Hymn by Johann Rist, 1642))
Date of composition 1723 (1723-1724;) in Leipzig, Germany
First published 1852 in Leipzig, Germany
Type Cantata
Tonality F Major
Catalogue BWV 20
Approx. duration 30 minutes
Spoken language German
Instruments Voice (Alto)
Voice (Tenor)
Voice (Bass)
Chorus/Choir
Trumpet
Oboe
Strings
Continuo
Autotranslations beta Jean-Sébastien Bach: O Ewigkeit, du Donnerwort en fa majeur, BWV 20 ""O eternity, you word of thunder""
Johann Sebastian Bach: O Ewigkeit, du Donnerwort in fa maggiore, BWV 20 ""O eternity, you word of thunder""
Johann Sebastian Bach: O Ewigkeit, du Donnerwort F-dur, BWV 20 ""O eternity, you word of thunder""