Ich bin ein guter Hirt, BWV 85, also known as "The Good Shepherd" Cantata, is based upon and begins with the words of Christ expressed in John 10:12. This would explain why Bach dispensed with the opening chorus, leaving the voice of Christ to the bass. Having Christ state his own words clearly and directly creates a sense of gravitas to the opening doleful aria. The opening continuo line and bass solo line foreshadow the chorale tune that will be heard in the final movement.
The acrobatic alto aria with virtuosic violoncello piccolo solo expresses a similar theme to that of the first aria. However the words are that of an observer, not Christ himself. The third movement is unusual in that it introduces a second chorale. The soprano soloist embellishes the chorale tune amidst a complex texture of two oboes and continuo. The chorale chosen, "The Lord is my Shepherd," is Psalm 23. This soprano aria serves as a turning point in the cantata from the solemnity of the opening arias to the pastoral images of the consequent movements.
The tenor recitative illustrates the great subtleties of Bach's representation of textural images. Full of clear and straightforward depictions, they almost beg for musical illustration: triplets for the wandering sheep, flowing sixteenth notes for the streams of Life, and severe harmonic turns for the “wolf of hell.” The pastoral tenor aria that follows is one of the most beautiful in the repertoire. This direct affirmation of the Savior’s love for us – “behold what love does" – never loses sight of the serious notion that all this was at the expense of Christ's blood. The insistent repeated notes on the words “Und hat am Kreuzesstamm vergossen” (“and on the trunk of the cross has poured [precious blood]”) bring a frigid moment to the mood of pastoral peace.
The closing chorale sums up the message of the entire cantata: The Shepherd, our Savior, is a matter of seriousness and gravity; but he also enables the true believer to discover pastoral redemption and contentment.
The "Good Shepherd" Cantata BWV 85 is modest in scope but musically on a very high level. It opens with a sober and beautiful bass aria with oboe and strings. The alto aria has an obbligato that was played variously on cello and violin in the several Leipzig performances. We play it here with violin obbligato. Two oboes accompany the solo soprano in a lovely setting of the chorale "Allein Gott in der Höh sei Ehr." An elaborate accompanied recitative leads the tenor into the beautiful and pastoral aria, one of the most appealing of all the tenor arias. A verse of the chorale "Ist Gott mein Schild und Helfersmann" ends the cantata.