Lobet den Herrn, alle Heiden, und preiset ihn, alle Völker! Denn seine Gnade und Wahrheit waltet über uns in Ewigkeit. Alleluja.1 Praise the Lord, all gentiles,2 and laud him, all peoples. For his grace and truth rules over us into eternity. Hallelujah.
(transl. Michael Marissen & Daniel R. Melamed)

1 Psalm 117:1-2 (the entire psalm).

2 In English Bibles and in translations of Bach’s motet libretto, this group is often given as “all [you] nations,” but what Luther expressly intended in his rendering as “alle Heiden” is a distinction between gentiles and Jews (certainly not between unbelievers—the “heathen”—and believers in the God of Israel). For his commentary on this psalm, Luther wrote (as quoted in the Calov Bible, which Bach owned), “Lobet den Herrn alle Heiden, das ist ja so viel gesagt, dass Gott nicht allein der Juden Gott sei, sondern auch der Heiden. ... Damit werden wir Heiden versichert und gewiss, dass wir auch zu Gott in den Himmel gehören, und nicht verdammt sein sollen, ob wir gleich nicht Abrahams leiblich Blut und Fleisch sein, wie die Juden sich rühmen, als wären sie allein Gottes Kinder, und Erben des Himmels, um der leiblichen Geburt willen, von Abraham, und den heiligen Erzvätern, Königen und Propheten” (“Praise the Lord all gentiles, which is indeed as much as having said that God is not the God of the Jews alone, but also of the gentiles. ... Thereby we gentiles become assured and certain that we also belong to God in the heavens, and shall not be damned, even though we are not Abraham’s biological [as opposed to spiritual] blood and flesh—like the Jews pride themselves [in being], as if they alone were God’s children, and heirs of heaven, on account of their biological birth from Abraham and the holy patriarchs, kings, and prophets”).