Note 9 — THE STANDARD CANTATAS.
Reading edition
There is yet a fourth rearrangement, which we may assign to 1730. The assertion is no doubt well founded that in this year the celebration of the Reformation Festival was considered of special importance, and kept accordingly; and it is evident that the cantata “Ein’ feste Burg” must have been intended for some such extraordinary solemnity.—
Spitta
, vol. ii. p. 470.
The Reformation Festival had no doubt a very distinct poetical sentiment of its own; and when any special occasion took the precedence, as in 1730 and 1739, the years of Jubilee, it would be misleading to seek for any close connection between the sermon and the cantata. Thus the cantata, “Ein’ feste Burg,” may very well have been connected with the sermon in 1730; still, it is possible that it was not written till 1739.—Ibid., vol. iii. p. 283.