The passover - See the notes at Matthew 26:2, Matthew 26:17.
A feast of the Jews - This is one of the circumstances of explanation thrown in by John which show that he wrote for those who were unacquainted with Jewish customs.

And the passover - was nigh - This happened about ten or twelve days before the third passover which Christ celebrated after his baptism. Calmet. For a particular account of our Lord's four passovers see the note on John 2:13.
For thirty days before the Passover there were great preparations made by the Jews, but especially in the last nineteen days, in order to celebrate the feast with due solemnity. Lightfoot supposes that what is here related happened within the last fifteen days. See Calmet's opinion above.

And the passover, a feast of the Jews, was nigh. This was the third passover, since our Lord's baptism, and entrance on his public ministry; see John 2:13. Whether Christ went up to this feast is not certain; some think he did not; but from what is said in John 7:1, it looks as if he did: how nigh it was to the feast, cannot well be said. Thirty days before the feast, they began to talk about it; and especially in the last fifteen days, they made preparations for it, as being at hand (b); and if there was now so long time to it, there was time enough for Jesus to go to it.
(b) T. Bab. Pesach. fol. 6. 1. Maimon. & Bartenora in Misn. Shekalim, c. 3. sect. 1.

passover . . . was nigh--but for the reason mentioned (John 7:1), Jesus kept away from it, remaining in Galilee.