Zion hört die Wächter singen is probably the most famous part of any cantata. It is the fourth part of BWV 140, and an absolute delight. Bach thought so too, he used it later for organ. So if none of these cantatas were interesting, this one at least deserves some attention.
The parabel of the wise and foolish virgins
Then the kingdom of heaven shall be likened to ten virgins who took their lamps and went out to meet the bridegroom. Now five of them were wise, and five were foolish. Those who were foolish took their lamps and took no oil with them, but the wise took oil in their vessels with their lamps. But while the bridegroom was delayed, they all slumbered and slept.
And at midnight a cry was heard: ‘Behold, the bridegroom is coming; go out to meet him!’ Then all those virgins arose and trimmed their lamps. And the foolish said to the wise, ‘Give us some of your oil, for our lamps are going out.’ But the wise answered, saying, ‘No, lest there should not be enough for us and you; but go rather to those who sell, and buy for yourselves.’ And while they went to buy, the bridegroom came, and those who were ready went in with him to the wedding; and the door was shut.
Afterward the other virgins came also, saying, ‘Lord, Lord, open to us!’ But he answered and said, ‘Assuredly, I say to you, I do not know you.’
Watch therefore, for you know neither the day nor the hour in which the Son of Man is coming.
Matthew 25:1-13, King James translation
So ten virgins are waiting for Jesus. Before he comes, five of them discover they don’t have oil enough for their lamps. They leave to fetch new and of course, at that moment He is coming. This parabel tries to tell you you have to have faith and wait, for He will come.
Bach created this most famous of all his cantatas for a day that almost never happened: the 27th Sunday after Trinitatis. That Sunday usually doesn’t happen, because it is after the end of the church year. Only when Easter is very early (in March) this Sunday exists.
If you want to know more, or listen to this cantate in a version from the Dutch Bach Society, try this: https://www.bachvereniging.nl/en/bwv/bwv-140/.
Sorry, 29. No more words.