Kantate, BWV 2 "Ach Gott, vom Himmel sieh darein"

Ach Gott, vom Himmel sieh darein (Oh God, look down from heaven), BWV 2, is a chorale cantata composed by Johann Sebastian Bach for the second Sunday after Trinity in 1724. First performed on 18 June in Leipzig, it is the second cantata of his chorale cantata cycle. The church cantata is based on Martin Luther's 1524 hymn "Ach Gott, vom Himmel sieh darein", a paraphrase of Psalm 12.

In the format of Bach's chorale cantata cycle, the words of the hymn are retained unchanged only in the outer movements, while an unknown contemporary librettist paraphrased the inner stanzas for recitatives and arias. Bach structured the cantata in six movements, setting the chorale tune in a chorale fantasia in the opening movement, and in a four-part setting in the closing movement. The two choral movements frame alternating recitatives and arias of three vocal soloists. Bach also used a four-part choir, and a Baroque instrumental ensemble of a choir of trombones, two oboes, strings and continuo. He set the first movement in "archaic" motet style, but the arias in "modern" concertante style, only occasionally reminiscent of the chorale tune.