Isaiah 63
10 But they rebelled, and vexed His Holy Spirit: therefore He was turned to be their enemy, and He fought against them.
To be vexed is an emotional response of which power as such is incapable. This is clearly a distinguishing mark of a person.
The Holy Spirit can be grieved.
Ephesians 4
30 And grieve not the Holy Spirit of God, whereby you are sealed unto the day of redemption.
He can be pleased or experience pleasure.
Acts 15
28 For it seemed good to the Holy Ghost, and to us, to lay upon you no greater burden than these necessary things.
He is able to speak His own mind and to call to service.
Acts 13 [see also 1 Timothy 4:1]
2 As they ministered to the Lord, and fasted, the Holy Ghost said, Separate me Barnabas and Saul for the work whereunto I have called them.
He is able to guide, to hear, and to show.
John 16
13 Howbeit when He, the Spirit of truth, is come, He will guide you into all truth: for He shall not speak of Himself; but whatsoever He shall hear, that shall He speak: and He will show you things to come.
He has the ability and the power to convict.
John 16
8 And when He is come He will reprove the world of sin, and of righteousness, and of judgment.
To be able to reprove successfully requires the intelligence which only a person could have. It necessitates the ability to recognize the need for reproof, the area in which it is needed and the way in which it must be given. No unintelligent power could ever have the capacity for doing such.
He is able to impart.
Romans 5
5 And hope makes not ashamed; because then love of God is shed abroad in our hearts by the Holy Ghost which is given unto us.
He is able to teach.
John 14
26 But the Comforter, which is the Holy Ghost, Whom the Father will send in my name, He shall teach you all things, and bring all things to your remembrance, whatsoever I have said unto you.
He is able to bring comfort and consolation.
Acts 9
31 Then had the churches rest throughout all Judea and Galilee and Samaria, and were edified; and walking in the fear of the Lord, and in the comfort of the Holy Ghost, were multiplied.
He is able to testify.
John 15
26 But when the Comforter is come, whom I will send unto you from the Father, even the Spirit of Truth, which proceeds from the Father, He shall testify of me.
To testify is to express a personal conviction. One must be a person to have this capacity.
He has a will of His own.
1 Corinthians 12
11 But all these work that one and the selfsame Spirit, dividing to every man severally as He will.
It is very clear that Jesus while upon this earth understood that the Holy Spirit was a real being who conducted an active personal work of commissioning, anointing, directing and empowering. He spoke of this in His sermon in Nazareth:
Luke 4
18 The Spirit of the Lord is upon me, because He has anointed me to preach the gospel to the poor; He has sent me to heal the broken-hearted, to preach deliverance to the captives, and recovering of sight to the blind, to set at liberty them that are bruised,
19 To preach the acceptable year of the Lord.
The Holy Spirit is a distinct Person and it is that He must be in order to do the things the Scriptures say that He does.
Only a person can think, speak, reprove, be grieved and so on. No other argument is needed beyond this to prove the point."
F.T.W.