12-15. when he, the Spirit of truth, is come . . . he shall not speak of himself--that is, from Himself, but, like Christ Himself, "what He hears," what is given Him to communicate.
      he will show you things to come--referring specially to those revelations which, in the Epistles partially, but most fully in the Apocalypse, open up a vista into the Future of the Kingdom of God, whose horizon is the everlasting hills.

JFB.