There are five extant motets firmly attributed to Bach -- a small number compared with his huge output of cantatas. Whereas the more plentiful cantatas served a liturgical purpose, the Lutheran church had no need of such short choral works, utilizing instead the large stock of motets already available in Leipzig and elsewhere. Bach's motets were therefore all composed for special occasions in Leipzig, primarily funerals -- events particularly suited to such serious contrapuntal compositions.
The text of BWV 228 ("Be not afraid, for I am with thee") clearly marks it out as falling within this category, although the exact circumstances for which it was composed remain unknown. Taken from two verses from chapters 41 and 43 of Isaiah and the hymn "Warum sollt ich mich denn grämen" by Paul Gerhardt, the text is divided into three interlinked sections; the opening phrase acts as a link that gives the motet strong structural coherence. Certain stylistic features of the writing suggest that the work may have originated earlier than Bach's time in Leipzig. It is scored for two four-part choruses, possibly intended to be supported by continuo bass (the original score was lost, leaving some issues of instrumentation open to question).
The motet opens with a largely homophonic eight-part chorus that introduces some striking dissonant harmony; this gives way to a more lightly scored four-part chorus, in which the hymn tune is heard in long notes in the soprano line. Later the eight-part opening phrase again returns, now embellished by the second stanza of the hymn. ~ Brian Robins, All Music Guide
