What is Spirit?
God (is) Spirit. God is Light. God is Love. His power, His radiance, and His affection are revealed in His Word.
It is a life force. God (is) Spirit and is the source of power.
It can be defined as "the invisible, nonphysical power of all life, action and intelligence.
There are many forms or expressions of spirit. A few examples: spirit of holiness, spirit of life, spirit of meekness, spirit of faith, spirit of promise, spirit of fear, spirit of grace, etc.
When we say that God is Light, it is clear that we are speaking figuratively. Light is a form of radiant energy. It is not God, but it is like God. The light of the sun and the stars together illustrate the great truth that He is Light.
1John 1:5 (KJV) This then is the message which we have heard of him, and declare unto you, that God is light, and in him is no darkness at all.
So, with love.
Love is a deep feeling of affection. We should not take the truth that God is Love literally, for He is more than a demonstrable quality, though His love is extremely precious.
1 John 4:8 He that loveth not knoweth not God; for God is love
But with spirit it is quite different. In John 4:24 most translations say “God is Spirit”. But the original Greek manuscripts omit the word “is”. Why? It states a fact, not a figure as with light and love. When we reflect that this is probably the only actual definition of the Deity found in Holy Scripture. This is the only assertion concerning His essence that we have.
Light and love are figures; but being spirit is a fact. In the original Greek this distinction is indicated by the absence of the verb “is”. From the Emphatic Diaglott Version: John 4:24 (Diaglott Version) A spirit the God; and those worshipping him, in spirit and truth it behooves to worship. This is no figure, like love and light. The Greek has it "God spirit." It is not one of His "attributes", it is His essence.
God is not a trinity
There is no reference in Scripture concerning the doctrine of the trinity for God is One, the Father of all. Christ Jesus is the Son of God the "First born of every creature, in whom all is created and in Whom all has its cohesion" (Concordant Literal Version - Col. 1:16-17).
1 Corinthians 8:6 (KJV) But to us there is but one God, the Father, of whom are all things, and we in him; and one Lord Jesus Christ, by whom are all things, and we by him.
Colossians 1:16 -17 (KJV) For by him were all things created, that are in heaven, and that are in earth, visible and invisible, whether they be thrones, or dominions, or principalities, or powers: all things were created by him, and for him: And he is before all things, and by him all things consist.
Let us therefore lay aside ineffective traditional opinion and accept the clear word of holy Scripture. It should be quite clear to all, that God's Holy Spirit is not a person, but is the manifestation and presence of God's own Spirit.
It is not a distinct personality from God Himself. No spirit has two personalities. How many Fathers did Christ have? We read in Matthew 1:18 that Mary was found pregnant by holy spirit. The messenger said that holy spirit shall be coming on you, and the power of the Most High shall be overshadowing you; wherefore the Holy One Who shall be born shall be called the Son of God.
Luke 1:35 (ASV) And the angel answered and said unto her, The Holy Spirit shall come upon thee, and the power of the Most High shall overshadow thee: wherefore also the holy thing which is begotten shall be called the Son of God.
It is clear that, if making by holy spirit made Him the Son of God, then God and this holy spirit must be a single "personality?"
As the Most High must be identified with the Father rather than the spirit, we find that the most explicit announcement which we have of His fatherhood gives us to understand (if we hold the doctrine of the trinity) that He had two Fathers! But the divine deduction is different. The holy spirit is not the Most High, but the power of the Most High. That power was the holy spirit of the Most High.
Once we see that the holy spirit is not a distinct spirit being from God, but is His spirit, the many difficulties which surround this subject vanish. This reconciles the passages in which it appears to act as a person with those in which it seems to be an impersonal power. Both are true of God's spirit, for it is the function of that spirit to operate as a power in God's creation and in His saints. If we wish to make a distinction between the "Giver" and the "gift," we will find that God Himself is the Giver, and His spirit the gift.
Acts 15:8 (KJV) And God, which knoweth the hearts, bare them witness, giving them the Holy Ghost (Spirit), even as he did unto us;
1Thess. 4:8 (KJV) He therefore that despiseth, despiseth not man, but God, who hath also given unto us his holy Spirit.
The Occurrence of Spirit (rûach Hebrew רוּח Strongs H7307) in the Old Testament
The word ruach occurs 389 times in the Hebrew Old Testament.
In the King James Version, it is rendered spirit in 237 passages. In the remaining 152 places it is translated in 22 different ways.
The meaning of the word is to be deduced only from its usage. The one root idea running through all the passages is invisible force. As this force may be manifested in different ways, so various renderings are necessitated, corresponding thereto. Ruach, in whatever sense it is used, always represents that which is invisible except by its manifestations such as: mind, breath, courage, anger, blast, and of course spirit.
It is also used for invisible spirit beings like angels Cherubim and evil angels.
And also as the invisible manifestations’ of the atmosphere like wind, whirlwind, windy air tempest, blast, quarters and sides.
A complete exposition on the use of the word ruach is provided by Dr. E.W. Bullinger in “The Companion Bible” https://www.companionbiblecondensed.com/.
And http://www.theheraldofgodsgrace.org/Bullinger/app9.html . https://www.companionbiblecondensed.com/
The Occurrence of Spirit (pneuma Greek πνεῦμα Strongs G4151) in the New Testament
Pneuma is the Greek word for spirit corresponding with the Hebrew ruach in the Old Testament. As to the Greek word (pneuma), we must consider the context and the usage.
According to Strongs Exhaustive Concordance it is:
a current of air, i.e. breath (blast) or a breeze; by analogy or figuratively, a spirit, i.e. (human) the rational soul, (by implication) vital principle, mental disposition, etc., or (superhuman) an angel, demon, or (divine) God, Christ's spirit, the Holy Spirit.
The word is somewhat complex, being found so often found in the New Testament. It is found in 234 verses is the King James Version. According to Dr. E.W. Bullinger it is used for God, Christ, holy spirit, it’s operation, new nature, man, character, other invisible characteristics, adverbially, demons, and resurrected body.
A complete exposition on the use of the word pneuma is provided by E.W. Bullinger in http://www.theheraldofgodsgrace.org/Bullinger/app101.html and “The Companion Bible” and https://www.companionbiblecondensed.com/.
In Conclusion
The spirit is a life force. God (is) Spirit and is the source of power.
It can be defined as "the invisible, nonphysical power of all life, action and intelligence.
There are many forms or expressions of spirit. A few examples: spirit of holiness, spirit of life, spirit of meekness, spirit of faith, spirit of promise, spirit of fear, spirit of grace, etc.
Some have claimed that God created the physical universe and everything in it from nothing. But they cannot point to any Divine declaration to substantiate that statement, for no such declaration exists. In the beginning God created the heavens and the earth by His Spirit.
The alternative to creation out of nothing, is the teaching of creation out of spirit. This means that matter is the form of which spirit is the reality. It indicates that the material is a product of the spiritual. This raises the question about man. Is man a spirit or a soul and what is the difference. More on this can be found on this page About Death.