well seem like we can't get an answer, so let's edify the Lord with the complete teaching knowledge of the Holy Ghost.
he who sits on the throne is he who stands and have the seven Spirits. scripture, Revelation 5:5 "And one of the elders saith unto me, Weep not: behold, the Lion of the tribe of Juda, the Root of David, hath prevailed to open the book, and to loose the seven seals thereof.
Revelation 5:6 "And I beheld, and, lo, in the midst of the throne and of the four beasts, and in the midst of the elders, stood a Lamb as it had been slain, having seven horns and seven eyes, which are the seven Spirits of God sent forth into all the earth.
Revelation 5:7 "And he came and took the book out of the right hand of him that sat upon the throne.
Revelation 5:8 "And when he had taken the book, the four beasts and four and twenty elders fell down before the Lamb, having every one of them harps, and golden vials full of odours, which are the prayers of saints.
let's break this down and understand. Jesus the "OFFSPRING", the "Son", the diversity of the Spirit, God himself sits on the throne. but he, Jesus the "ROOT", the Father, the Source, God himself, the Spirit is Standing. and notice the "ROOT", (the Lamb) not the "Offspring", (the Lamb of God) but the "ROOT" of David is sent fort into all the earth, (verse 6). question who was sent into all the EARTH? answer, the Holy Spirit, who is the "ROOT", symbolising before David, "Spirit".
but here's the revelation is not the Lord Jesus the "ROOT" and the "OFFSPRING" of David? let the bible speak. Revelation 22:16 "I Jesus have sent mine angel to testify unto you these things in the churches. I am the root and the offspring of David, and the bright and morning star". BINGO, case closed, Jesus IS THE "ROOT" & "THE OFFSPRING". Jesus is the one who sits on the throme and it is Jesus who is standing in glory of his resurrection.
so, knowing this, it is Jesus, the Spirit, the Holy Spirit who is Father and son that came on Pentecost. can we verify this by scriptures, yes, John 14:23 "Jesus answered and said unto him, If a man love me, he will keep my words: and my Father will love him, and we will come unto him, and make our abode with him".
we, yes, the Spirit of God, and the Spirit of Christ, the same Spirit, (see Romans 8:9). Oh how clear the bible comes together. we is the Diversified state of the Spirit. the we of Genesis 1:26 that was to come "diversified" in flesh, (per Romans 5:14b). look how the bible just fit together, scripture testifying of scripture.
John 14:16 "And I will pray the Father, and he shall give you another Comforter, that he may abide with you for ever;
John 14:17 "Even the Spirit of truth; whom the world cannot receive, because it seeth him not, neither knoweth him: but ye know him; for he dwelleth with you, and shall be in you.
John 14:18 "I will not leave you comfortless: I will come to you.
the I is the Father and the Son as said in John 14 verse 23.
someone here said, "they sent the Holy Ghost". the Holy Ghost is God himself is both the OFFSPRING and the ROOT.
Oh how men just handle the scriptures incorrectly.
PICJAG.
a re-read of this post might be nessary for clarity.