The article deals with the detailed analysis of the instrumentation of the soprano aria “Laßt der Spötter Zungen schmähen” (no. 5), in which the first violin part standing out fragmentarily from the unison of the high-pitched strings accompanying the singer. The Cantata BWV 70, created by Bach during his Weimar period, was revived with a few alterations in Leipzig in 1723. The author covers the issue of the number of players in Bach’s orchestra during these periods and concludes that most likely each violin part was performed by three musicians and the viola part was performed by two musicians in Leipzig; while in Weimar the cast was much more limited and there was only one performer for each instrument. In the handwritten pieces of the first violin part of the soprano aria, the indicated dynamics coincide with the beginning and ending of pauses in the second violin and viola parts. The comparison of this peculiar feature of the notation with other manuscripts of Bach’s compositions, some improvisatory traits of the piano fragments, and the potential opportunity to create timbre contrast suggests that the dynamic markings forte — piano become an alternative to indications tutti — solo, and individual fragments of the aria, marked with piano, should be performed by a soloist. We do not know for certain, what was the exact sound of this music in 1723. However, at present, having much superior performing resources than Bach had in Leipzig, we can assign separate pieces to a soloist, regardless of the number of orchestra musicians. Thanks to this solution, music appears much more convincing and gains a certain splendor, that is supported by the rare examples of contemporary performing practice