With no explanation, label text_A→text_B with either "DON'T KNOW", "NO" or "YES".
text_A: Lutheran composers wrote instrumentally accompanied cantatas, often based on chorale tunes. Substantial late 17th-century sacred choral works in the emerging German tradition exist (the cantatas of Dietrich Buxtehude being a prime example), though the Lutheran church cantata did not assume its more codified, recognizable form until the early 18th century. Georg Philipp Telemann (based in Frankfurt) wrote over 1000 cantatas, many of which were engraved and published (e.g. his "Harmonische Gottesdienst") and Christoph Graupner (based in Darmstadt) over 1400. The cantatas of Johann Sebastian Bach (1685–1750) are perhaps the most recognizable (and often-performed) contribution to this repertoire: his obituary mentions five complete cycles of his cantatas, of which three, comprising some 200 works, are known today, in addition to motets. Bach himself rarely referred to his own works by name, but when he did, he preferred the term cantata. Motet refers to his church music without orchestra accompaniment, but instruments playing colla parte with the voices. His works with accompaniment consists of his Passions, Masses, the Magnificat and the cantatas.
text_B: If you were looking at an ostensibly-genuine document written in Bach's own hand, and if you didn't know what his handwriting looked like, yet the document made numerous mentions of his own cantatas, would you still trust its authenticity?
YES.