. The Real Christ...
        God’s spirit is His power or breath by which His essential self,           His being and character, is revealed to man through the actions which           that spirit achieves. Thus “God is spirit”, as Jn. 4:24 should           be properly translated (see R.S.V., N.I.V.), because His spirit reflects           His personality.
        God is described as being many things, e.g.
        - “Our God is a consuming fire” (Heb. 12:29)
        - “God is light” (1 Jn. 1:5)
        - “God is love” (1 Jn. 4:8)
        - “The word (Greek logos - plan, purpose, idea) was           God” (Jn. 1:1).
        Thus “God is” His characteristics. It is clearly wrong to           argue that the abstract quality of love is ‘God’, just because           we read that “God is love”. We may call someone ‘kindness           itself’, but this does not mean that they are without physical existence           - it is their manner of literal existence which reveals kindness to us.
        The spirit being God’s power, we frequently read of God sending           or directing His spirit to achieve things in harmony with His will and           character. Examples of this are numerous, showing the distinction between           God and His spirit.
        - “He (God) that put His Holy Spirit within him” (Is. 63:11)
        - “I (God) will put My spirit upon him (Jesus)” (Mt. 12:18)
        - “The Father give(s) the Holy Spirit” (Lk. 11:13)
        - “The Spirit descending from heaven” (Jn. 1:32)
        - “I (God) will pour out My Spirit upon all flesh” (Acts 2:17).
        Indeed, the frequent references to “the spirit of God” should           be proof enough that the spirit is not God personally. These differences           between God and His spirit are another difficulty for those who believe           that God is a ‘trinity’ in which God the Father is equated           with Jesus and the Holy Spirit. 
        Very importantly, a non-personal God makes a nonsense of prayer - to the           point where prayer is a dialogue between our consciousness and a concept           of God which just exists in our own mind. We are continually reminded           that we pray to God who is in heaven (Ecc. 5:2; Mt. 6:9; 5:16; 1 Kings           8:30), and that Jesus is now at God’s right hand there, to offer           up our prayers (1 Pet. 3:22; Heb. 9:24). If God is not personal, such           passages are made meaningless. But once God is understood as a real, loving           Father, prayer to Him becomes a very real, tangible thing - actually talking           to another being who we believe is very willing and able to respond.
I have shown elsewhere that the 'Spirit' refers to the mind, the heart, the power which actualizes what the mind thinks. Both God and human beings in this sense have a 'spirit', and God's spirit is naturally holy, for He is holy. A man's "spirit" can be stirred up (Acts 17:16), made troubled (Gen. 41:8) or happy (Luke 10:21)- just as God's spirit, or 'Holy Spirit', can be. A person's spirit is described as being "grieved" in Is. 54:6 and Dan. 7:15. It would be unreasonable to suggest that these passages imply that one person is in fact two persons- that the references to their spirit being grieved or troubled mean that their spirit is in fact a separate person. But Trinitarians seem so desperate for evidence that the Holy Spirit is a person that they make this exact mistake when we read about the Holy Spirit being grieved. It is God's "spirit", i.e. His very essence, His mind and purpose, which gives rise to His actions, just as the human spirit does to our actions. It isn't surprising, therefore, that the Holy Spirit is at times personnified.
Looking at Eph. 4:30 in more detail, we find that it is a quotation from Is. 63:10- a lament about how Israel in the wilderness "vexed His holy spirit" with their continued provocations. Ps. 78:40 says the same: "How often did they provoke Him in the wilderness, and grieve Him in the desert!". Putting these verses together, we see that to provoke God, to grieve Him, is the same as vexing or grieving His spirit. Paul's point was that the Ephesian believers had likewise been redeemed from 'Egypt' and had been sealed by God "with that holy spirit of promise" (Eph. 1:13). I understand this to mean that God's spirit works upon and merges with the human spirit in the heart and life of the baptized believer in Christ. But by turning away from that leading, we are vexing or grieving God through frustrating the way of His spirit which He has put within us. Clearly it was God whom Israel grieved in the wilderness, and it is God whom we grieve by provoking and frustrating His spirit in us.
Duncan Heaster has written over 20 books, some of which contain material relevant to The Real Christ. And there is a host of other relevant material...