Ed Myskowski wrote (February 12, 2012):
Introduction to BWV 138 -- Warum betrübst du dich, mein Herz?
This week we continue Trinity season cantatas with BWV 138, the first of three works for the 15th Sunday after Trinity.
Details of text, commentary, recordings, and previous discussion are accessible via: http://www.bach-cantatas.com/BWV138.htm
The link to commentary by Julian [Mincham] is especially recommended as an introduction to listening, music examples included.
The BWV 138 page has convenient access to notes from the Gardiner, Koopman (notes by Christoph Wolff), Suzuki, and Leusink CD issues, via link beneath the cover photo. The Kuijken CD also includes his own informative notes (not linked), and is recommended for those who enjoy (or would like an introduction to) OVPP performance practice.
The chorale text and melody are accessible via links at the BWV 138 page. Francis Browne has recently added new commentary on the cantata texts to his interlinear translations, linked via [English 3]. We can expect these to continue, not necessarily weekly. Douglas Cowling and William Hoffman are also posting relevant to chorales and other music for the Lutheran Church Year, accessible via LCY pages.
I do not always take the time to check all links before posting. Special thanks to the folks who provide timely corrections.