O Ewigkeit, du Donnerwort (O eternity, you word of thunder),[1] BWV 60, is a church cantata for the 24th Sunday after Trinity composed by Johann Sebastian Bach.

The opening movement is a chorale fantasia containing a stanza from Johann Rist's "O Ewigkeit, du Donnerwort" and a biblical quotation from the Book of Genesis.

The fourth movement is a dialogue between Fear and Christ (vox Christi, sung by a bass), who quotes "Selig sind die Toten" from the Book of Revelation.

Its melody begins with an unusual whole-tone sequence which inspired Alban Berg in the 20th century to incorporate Bach's setting in his Violin Concerto.

Bach wrote the cantata for the 24th Sunday after Trinity in his first year as Thomaskantor and music director of Leipzig's main churches.

The first movement, "Herr, ich warte auf dein Heil" (Genesis 49:18),[3] spoken by Jacob on his deathbed, expresses hope against the fear conveyed in the chorale.

[8] In the fourth movement, Selig sind die Toten (Blessed are the dead, Revelation 14:13)[3] is the answer to the preceding recitative of Fear.

Bach had composed a similarly structured cantata three weeks before, entitled Ich glaube, lieber Herr, hilf meinem Unglauben, BWV 109, which also featured a dialogue between Fear and Hope, given to one singer.

In O Ewigkeit, du Donnerwort, he assigns Fear to the alto and Hope to the tenor, and he has them sing three movements in dialogue.

In movement 4, Fear is answered instead by the bass, the vox Christi (voice of Christ), with "Selig sind die Toten".

He scored the work for three vocal soloists (alto (A), tenor (T) and bass (B)), a four-part choir only in the closing chorale, and a Baroque instrumental ensemble: horn (Co) to support the chorale tunes, two oboes d'amore (Oa), two violins (Vl), viola (Va), and basso continuo (Bc).

[4][10] The chorale, the first stanza of Rist's hymn "O Ewigkeit, du Donnerwort" (O eternity, you word of thunder),[1] is sung by the alto (Fear), reinforced by the horn.

[2] From the second Stollen of the chorale, the tenor as Hope responds with Jacob's words, "Herr, ich warte auf dein Heil" (Lord, I await your salvation).

[2] Three different sections are developed in a similar way: Fear begins, "Mein letztes Lager will mich schrecken" (My final bier terrifies me),[1] Hope answers, "Mich wird des Heilands Hand bedecken" (My Savior's hand will cover me),[1] both argue, and Hope has the last word.

Fear begins "Der Tod bleibt doch der menschlichen Natur verhaßt" (But death remains hateful to human nature)[1] in secco recitative, but three times the bass as the vox Christi quotes the consoling words from Revelation "Selig sind die Toten" (Blessed are the dead)[1] as an arioso, each time expanded, following the scheme a ab abc.

[12] Dürr notes: "The fascination of these ariosos lies in their memorable and eloquent melodic line which presents the text in heightened speech.

[13] The melody begins with an unusual sequence of four notes progressing by steps of major seconds (whole tones), together spanning the interval of a tritone, also called "diabolus in musica".