In cantata 179, the second pair of recitative and aria has the recitative, for bass, dramatize the moment in the temple when the publican cries out for God’s mercy, and the soprano aria, accompanied only by two oboes da caccia with independent parts (and the continuo), sings lovingly to God for His rescue of the sinner, whose transgressions, devouring his vitals with incurable disease, otherwise would cause the sinner to sink irretrievably into the slime. Bach depicts the likelihood of such a descent by having the voice, twice, the second time on a descending chromatic scale, fall lower and lower in its range, till the oboes pause, and the voice is exposed in the ooze into which it would disappear. At the end of the second iteration, there are two beats of complete and beseeching silence. This moment occurs at the end of the middle section of the aria, before the through-composed da capo. The moment is made the more supplicative by the gorgeously hued soprano line in the middle section of the aria, for it is here that Bach has the heart bring forth its entreaty of need, and waits, as it ends, in the silence of two beats of eternal time.
From the second book, in progress, on the Trinity cantatas of J.S. Bach, in the series that begins with J.S. Bach: Cantatas for Trinity I through VII