John Lightfoot on John 16:12

[Ye cannot bear them now.] Those things which he had to say, and they could not bear yet, were the institution of the Christian sabbath, and the abolishing of the Jewish (the reason and foundation of which, viz. his resurrection, they yet understood not); the rejection of the Jewish nation, when they expected 'that the kingdom should be restored to Israel,' Acts 1:6; the entire change of the whole Mosaic dispensation, and the bringing in of all nations in common within the pale of the church: these and such like things as these belonging to the kingdom of God, Acts 1:3, they could not yet bear. For though he had plainly enough discoursed to them the destruction of Jerusalem, Matthew 24, yet it is a question, whether they apprehended either that their whole nation must be utterly cast off, or that the rites of Moses should be antiquated, although he had hinted something of this nature to them more than once.