Sebastian Bach (1685-1750), Kreuzstabkantate (1731), BWV 56
Similar to Baroque literature, the music of the Baroque period is characterized by the frequent use of contrasting elements. This tendency manifests itself, for instance, in the development of extremely high-pitched and low-pitched instruments. But even the very idea of counterpoint - a compositional technique which flourished during the period in unprecedented diversity and complexity - creates contrasts by setting note against note: punctus contra punctum. One of the best-known pieces which make use of this technique is J. S. Bach's Die Kunst der Fuge (The Art of Fugue 1748-50); but the contrapunctal interweaving of parts is also very common in Baroque vocal music, for example in Bach's famous solo cantata Ich will den Kreuzstab gerne tragen (I will the cross-staff gladly carry). Here, the sturdy ostinato-like accompaniment for the continuo is set against two fluid vocal and instrumental lines with expressive melismas to heighten the joy and hopefulness expressed in the text:
Within the strict da capo setting of the aria, the voice imitates the instrumental style by its use of coloraturas and figuration. In complementing the thorough bass with a brilliant, high-pitched oboe part, Bach created the lively polyphonic dialogue of the two parts. They "concert" in the double etymological sense of the word: They dispute and compete, yet basically agree. The theme is repeated, reversed and varied in both parts to underline joy and hope as the predominant "effects" and "affections" of the aria. The discourse of the two parts, so different both in pitch and character, is a prime example of the use of contrast in Baroque music.
Johann Sebastian Bach, "Endlich wird mein Joch"