“Gelobet seist Du, Jesu Christ”, BWV 604, is a melody short corale with some degree of ornamentation. Written in G major, but with no f#, it has a mixolidian character (apud, Stinson, “The Orgelbüchlein”, p. 81, 1999, Oxford University Press).
The inner voices are treated according to German baroque music practice, as Bach did extensively in the “Neumeister Chorales” (the “hooked” progression of the inner parts), “rocking of the cradle”, according to Hermann Keller, in “The Organ Works of Bach”, p. 203, 1967 – Peters Corporation”).
The origin of the text is the 14th century (a sacred song, concluding with a Kyrie eleison (a Leise): “Gelobet seis Du, Jesu Christ,/ Dass Du Mensch geboren bista/ Von einer Jungfrau, das ist wahr;? Des freuet sich der Engel Schar/ Kyrieleis!”. (From the Latin sequence “Grates nunc omnes reddamus”, 14th century. Translated by Martin Luther, 1524.)