From: John 16:12-15
The Action of the Holy Spirit (Continuation)
(Jesus said to His disciples,)  "I have yet many things to say to you, but you cannot bear them now.  When the Spirit of truth comes, He will guide you into all the truth; for He will not speak of His own authority, but whatever He hears He will speak, and He will declare to you the things that are to come.  He will glorify Me, for He will take what is mine and declare it to you.  All that the Father has is Mine; therefore I said that He will take what is Mine and declare it to you."
13. It is the Holy Spirit who makes fully understood the truth revealed by Christ. As Vatican II teaches, our Lord "completed and perfected Revelation and confirmed it...finally by sending the Spirit of truth" (Vatican II, "Dei Verbum", 4). Cf. note on John 14:25-26.
14-15. Jesus Christ here reveals some aspects of the mystery of the Blessed Trinity. He teaches that the Three Divine Persons have the same nature when He says that everything that the Father has belongs to the Son, and everything the Son has belongs to the Father (cf. John 17:10) and that the Spirit also has what is common to the Father and the Son, that is, the divine essence. The activity specific to the Holy Spirit is that of glorifying Christ, reminding and clarifying for the disciples everything the Master taught them (John 16:13). On being inspired by the Holy Spirit to recognize the Father through the Son, men render glory to Christ; and glorifying Christ is the same as giving glory to God (cf. John 17:1, 3-5, 10).
Source: "The Navarre Bible: Text and Commentaries". Biblical text taken from the Revised Standard Version and New Vulgate. Commentaries made by members of the Faculty of Theology of the University of Navarre, Spain. Published by Four Courts Press, Kill Lane, Blackrock, Co. Dublin, Ireland. Reprinted with permission from Four Courts Press and Scepter Publishers, the U.S. publisher.