It is not proved beyond any doubt what kind of "corno" was meant in the autograph because the original parts are lost and Agricola's copy does not mention any "corno" at all.
Lyrics
author unknown; mvt. 1: Psalm 143:2; mvt. 6: stanza 11 from ‘Jesu, der du meine Seele’ (1641) by Johann Rist (1607–1667). Link to lyrics
Edition
NBA I/19, S. 1 (Robert L. Marshall, 1985) – Critical report (1989), S. 11;
BG 23, S.119 (W. Rust, 1876)