A.T. Robertson Commentary John 10:40

"And he went away again beyond the Jordan into the place where John was at the first baptizing; and there be abode." — John 10:40 (ASV)

Again (παλιν). Referring to 1:28 (Bethany beyond Jordan). Παλιν does not mean that the other visit was a recent one.

At the first (το πρωτον). Adverbial accusative (extent of time). Same idiom in 12:16; 19:39. Here the identical language of 1:28 is used with the mere addition of το πρωτον (οπου ην Ιωανης βαπτιζων, "where John was baptizing").

And there he abode (κα εμενεν εκε). Imperfect (continued) active of μενω, though some MSS. have the constative aorist active εμεινεν. Probably from here Jesus carried on the first part of the later Perean Ministry (Luke 13:16–22:10) before the visit to Bethany at the raising of Lazarus (John 11:1–44).