My German is very basic (at best) but I sometimes have to write little blurbs about music and sometimes the music I write about is German. Since it's getting close to Christmas, I needed to write something about the Bach chorale Jesus bleibet meine Freude (usually translated into English as Jesu, Joy of Man's Desiring, although that bears little resemblance to the original). And when I typed the title, the grammar-checker I use complained that I had misspelled "bleiben". My editor hates it when I misspell words, so I checked all the versions I could find online, and they almost universally wrote "bleibet". (One of them used "bleibt", but it turned out to be a typo, since "bleibet" clearly appears on the album cover.) So I'm sure "bleibet" is correct, but I'm curious as to why.
According to Duden's conjugation for bleiben, the only place "bleibet" shows up is in the second person plural subjunctive "ihr bleibet". It's hard for me to see how this could be appropriate, although I could be missing some subtlety; I would have thought that the correct conjugation would be "bleibt" (third person singular, present tense).
The text which Bach adapted for his cantata was written around 1665 by Martin Jahn (or Janus) (according to en.wikipedia/de.wikipedia, which cites the work in both language editions as Jesus bleibet meine Freude). So I suppose it could be an archaic usage. Or it could be an phonological modification to fit the meter, which requires "bleibet" to be sung as two syllables.
In pursuit of a possible archaic usage, I noted that the English adaptation (it's certainly not a translation) uses the archaic Latin vocative "Jesu", which must have sounded poetic but also doesn't seem to me to be appropriate; the phrase is not addressed to Jesus, even metaphorically. And as far as my research indicated, the original text in German was always "Jesus". (I did find several references in German which call it "Jesu bleibet meine Freude", but I suspect that these are the result of contamination by the English title.) But if the phrase were considered to address Jesus rather than referring to him, then a different conjugation would be appropriate, presumably "bleibst".
Anyway, if someone has some insight which could satisfy my curiosity, I'd be grateful. In the meantime, I'm just ignoring the squiggle produced by my grammar-checker (as I often have to do).