The orchestra is full of countless sound combinations. In Bach's time, the orchestra was smaller and these new expressions mostly hadn't yet been explored. But in the "Wohl euch" aria from the Pentecost cantata O ewiges Feuer, o Ursprung der Liebe, Bach experimented with a new language in tone color with violins and flutes. The Pentecost story of the cantata is a sort of reverse Tower of Babel; apostles were given a gift of the Spirit's fire and could suddenly communicate in many languages. Bach, a Protestant, took advantage of writing the church's vocal music in the people's language of German rather than the obtuse Latin of traditions past. Similarly, his orchestration -- way ahead of its time -- points to a new way of "speaking" to us musically.