Gott der Herr ist Sonn und Schild (God the Lord is sun and shield), BWV 79, is a church cantata by Johann Sebastian Bach. He composed it in Leipzig in 1725, his third year as Thomaskantor, for Reformation Day and led the first performance on 31 October 1725. Bach performed the cantata again, probably in 1730. He later reworked the music of the opening chorus and a duet again in his Missa in G major, BWV 236, and the music of an alto aria in his Missa in A major, BWV 234.