In like manner we may have such a second-hand knowledge of the Paraclete as we find in the Holy Scriptures and in the testimony of persons filled with the Spirit, while strangers to the personal Holy Spirit. It is one thing to know much about Him; it is quite a different thing to have an intuitive perception of Him, and to feel the thrilling and transforming touch of His hand, and to commune with Him by day and by night more intimately than with any earthly friend. This is the kind of knowledge invoked in the so-called apostolic benediction. We do not understand that in our knowledge of the Holy Spirit we differentiate Him from the Father and the Son, though some eminent Christians testify to an acquaintance with each Person of the adorable Trinity, one in substance, but three in subsistences. If such a knowledge has been given to any believers, it is quite exceptional. It may be universal in the future world; it is certainly very rare in this. In our present state it is enough for us to receive the love of God and the grace of the Lord Jesus Christ commingled in one blissful stream descending through the channel of the Holy Ghost. A distinctive knowledge of each person would tend to divide the divine substance and to lead to tritheism, three Gods.
In the scheme of revelation the Father revealed Himself in His incarnate Son. After His visible form was received by the cloud which hid Him from the eyes of His gazing disciples on the day of His ascension, the Paraclete was sent down to testify of the absent God-Man, to keep Him in the world's thought and to glorify Him who came to glorify the Father. Hence the Paraclete glorifies both the Father and the Son when He glorifies the Son. Hence Paul's prayer for the Ephesian church, "That the Father would give them the Spirit of wisdom and revelation in the knowledge of him." This and other texts show that it is not the mission of the Comforter to give prominence to Himself, but to Christ, to whom He bears witness. Thus
"...when a messenger comes to tell a king, when a witness gives a testimony for his friend, neither speaks of himself. And yet, without doing so, both the messenger and the witness, in the very fact of giving their evidence, draw our attention to themselves, and claim our recognition of their presence and trustworthiness. And just so the Holy Spirit, when He testifies of Christ and glorifies Him, must be known and acknowledged in His divine commission and presence." (Andrew Murray.)
It is in this sense that we are to have a knowledge of the Paraclete while He holds up a light for us to see the Father in His adorable Son.
— from The Gospel of the Comforter, Chapter 22.