IV Osanna, Benedictus, Agnus Dei et Dona nobis pacem

1. Osanna in excelsis

2. Benedictus qui venit

3. Osanna in excelsis

4. Agnus Dei

5. Dona nobis pacem

For the only time during the work, the sprightly Osanna is set for a double (eight-part) choir. It is based on the opening chorus of the secular Cantata No. 215 (1734) "Preise dein Glucke, gesegnetes Sachsen" ("Praised be your fortunes, ye most blessed Saxons"), a piece performed in honour of the coronation of Augustus III as King of Poland. As one critic has observed, "In a society which regards Kings as divinely appointed by God, he [Bach] would have seen no incongruity in using the same music to praise the King of Poland and the King of Heaven".

The Benedictus, apparently the vestige of a lost tenor aria, is unusual in that Bach wrote an obbligato part but left the instrument unspecified. The part suits best the flute or violin; in this performance it will be played on the flute. With its slow, long, graceful vocal and instrumental lines, this movement is an evocation of serene love and longing.

The Agnus Dei, which follows a straight reprise of the Osanna, is scored for alto solo matched to a low-lying ritornello for strings. It uses almost the same music as "Ach bleibe doch, mein liebstes Leben" ('Oh, stay with me, my dearest life'), from Cantata No. 11 (The Ascension Oratorio).

The Dona nobis pacem reprises the Gratias, bringing the B Minor Mass to a triumphant close and linking majestically the concepts of peace, praise and gratitude to the Almighty.