The Bible teaches that the Father, Son, and Holy Spirit are one God (Ge 1:26, 27; 2:7; De 6:4; Mt 1:23; 3:16-17; 28:19; Mk 12:29, 32; Jn 10:30, 38; 12:45; 14:10; Ro 8:3;1Co 8:4; 2Cor. 4:4; Col 1:15: Ep 4:6; Ph 2:5-7; 1Ti 2:5), understanding this teaching in accordance with John 4:24, “God is Spirit” reveals that the Father, Son, and Holy Spirit are the same Spirit.
To help us understand the Oneness of God, let us look at God’s statement in Genesis 1:26, "Then, God said, 'Let us make man in our image, in our likeness....’” The result of this statement shows Father, Son, and Holy Spirit are one God and the same Spirit. Mankind bears the image and likeness of God, not images and likenesses of multiple gods, even though God had said, "Let us make...." Genesis 1:27 summarizes, “So God created man in His own image; in the image of God He created him; male and female He created them.” Other chapters in Genesis continue to attest to man bearing a singular image and likeness of God, “God created man…in the likeness of God” (5:1); “in the image of God, He [God] made man” (9:6). James refers to it also, “With the tongue we praise our Lord and Father, and with it we curse men, who have been made in God’s likeness (Ja 3:9) (See also 1Cor 11:7).
In Matthew, Jesus authorizes His disciples to “...go and make disciples of all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit...” (28:19); this too, teaches about the Oneness of God. When a person returns to God through Jesus, it is a new beginning for the person (2 Cor. 5:17). Paul explains it as “the new self, which is being renewed in knowledge in the image of God, its Creator” (Col 3:10). Thus, similar to the creation in Genesis, the "new self" must have its beginning in the three, yet, one God, same spirit. God knows what He is doing; baptism must be in the name of all three.
The teaching that “God is Spirit” (Jn 4:24) is not new to the Christian faith. However, it seems that though our hearts believe it, for some of us, our minds are not aware of the intricacy of it. For, it is not so much that "God is Spirit," but that the Spirit is God! Not understanding this probably accounts for the difficulty many believers face when they desperately try to explain how the Father, Son, and Holy Spirit are one God. For it is not so much that they are one God but that they are the same Spirit! We know this Spirit as the LORD. Since the LORD is the Creator, the only one who gives life, we should worship and serve Him. Fear Him and keep His commandments (Ecc 12:13); He is God! Even if people fail to worship and serve Him, refusing to acknowledge Him (Rom 1:28), He is still God.
We have to begin thinking Spirit. The Sovereign Spirit is our LORD, our reality, our Father, Son, and Holy Spirit, our God!