One of the mistakes made by Oneness Pentecostals is the failure to recognize what the Scriptures teach concerning the unity of the Godhead. They err in their use of all the passages which talk about there being "one God" because they do not understand how three Persons that have Divine nature can be one. Thus, they conclude that there is only one person possessing Divine nature, but that this one person manifests Himself as Father, Son and Holy Ghost.
Jehovah's Witnesses err similarly respecting the Godhead concluding that Jesus and the Holy Spirit are not Divine. They recognize two persons in Christ and the Father, but they assign Christ the nature of angels. To them the Holy Spirit is a personification of the Father's actions and energies, but certainly not a third person possessing Divinity. Thus, they are unitarian in their concept of the Godhead.
Some brethren err in their concept of the unity of the Godhead when they fail to recognize that unity of essence and unity of purpose do not necessitate union in action or preclude diversity in function. The Godhead acts when all three are acting or when One acts as the agent of all. Furthermore, submission of one member of the Godhead to another does not result in the disruption of the Godhead or the removal of the submitting member from the Godhead.
What do the Scriptures teach about the Godhead? How is it that three persons can be one God?
In Deuteronomy 6:4, Moses declares, "Hear, O Israel: The Lord our God is one Lord." Moses is not affirming that there is but one person in the Godhead because he clearly identifies a plurality (Genesis 1:1, 2, 26; 3:22; 11:7). Rather, Moses assures Israel that there is only one true Godhead in contrast to the many deities which the heathen worshipped (cf. Acts 17:23,24). Moses says, "There is none other beside Him" (Deuteronomy 4:35).
However, there are three persons which exist as God: the Father (1 Peter 1:2), the Son (Acts 20:28; Hebrews 1:8) and the Holy Spirit (Acts 5:3,4). These three have the same essence and are necessarily equal in their attributes.
A poor illustration, but one to which we can relate, is that of our own humanity. The Scripture says that God "hath made of one blood all nations of men" (Acts 17:26). Each one of us is distinct from the other in will, thought and the other characteristics which determine personality. However, we all share the same essential attributes and qualities that make humanity human. Similarly, the Father, the Son and the Holy Spirit while distinct in personality share the same essential qualities that make Deity Divine.
Jesus has the nature of God (John 1:1) as do the other persons in the Godhead (John 1:2; Genesis 1:2; 1 Timothy 1:1). Yet , Jesus is not the Father (2 John 3) and the Father is not Jesus (1 John 4:14). Neither is the Holy Spirit the Father (John 15:26), or the Father the Holy Spirit (John 14:26). Jesus is not the Holy Spirit (Acts 10:38), and the Holy Spirit is not Jesus (John 16:13-15). Three distinct persons having the same essential nature.
The unity of the Godhead is not limited to essence or nature. This unity extends to purpose and will (John 10:30). The Father, the Son and the Holy Spirit are one in work (John 4:34; 16:13-15), creation (Ephesians 3:9; Genesis 1:2; Job 26:13-14), authority (Revelation 2:1,7; Hebrews 1:1-4), love (John 14:21-23; Romans 5:5), witness (John 8:18;16:8-14), doctrine (John 7:16; 14:26; 16:15), will (John 6:38; 16:8-13) and judgment (John 5:22, 30; 16:11).
The unity of the Godhead in purpose and will is best illustrated by the marriage relationship. Moses wrote, "they shall be one flesh" (Genesis 2:24; cf. Matthew 19:6). The husband and the wife do not become one person, but are united now with one common purpose and one common will. Similarly, Jesus prayed that believers become one "as Thou, Father art in me, and I in thee, that they also may be one in us" (John 17:21). The many believers did not merge to form one person, but they merged their purpose and will into one. Likewise, the Father, the Son and the Holy Spirit are one in purpose and will.
The unity of the Godhead does not preclude a diversity of function among the members of the Godhead. It does not require that all three members act in order for the Godhead to act. Each member of the Godhead is God, not just one-third of God. Thus, the Godhead may work through one of its members and, in relation to Their will, each may perform a different function.
For example, in Creation this diversity of function is clearly present. The Father planned the creation (Genesis 1:1-2; Jeremiah 51:14-15; Psalms 33:9), the Word executed the Father's plan (John 1:1-3; Colossians 1:16; Hebrews 1:1-2) and the Holy Spirit completed it (Genesis 1:2; Job 26:13; Psalms 104:30; cf. Genesis 2:7). Their relation to each other is much like that of Architect, Contractor and Carpenter.
This diversity of function is also seen in the process of redemption. the Father was the planner (Ephesians 1:8-11; 2 Timothy 1:9), Christ was the sacrifice (John 4:34; Ephesians 1:3-7; 2 Timothy 1:10; 1 Peter 1:18-20) and the Holy Spirit was the revealer (John 16:8-13; Ephesians 3:1-4; 1 Corinthians 2:9-10). Each member of the Godhead provided a distinct Divine function which contributed to the completion of Their common purpose and will. Diverse functions, but only one Godhead.
Still another example of this diversity in function within the one Godhead is demonstrated in the Incarnation of Christ. While there are many mysteries associated with the manifestation of God in the flesh (1 Timothy 3:16), the three distinct roles of the members of the Godhead are revealed. The Father sent the Son (John 3:16; 8:42; 12:44-45), Jesus worked the works of Him that sent Him (John 5:30, 36-37; 6:38; 9:4; ) and the Holy Spirit was the agent of God's power in Jesus (Matthew 12:18, 28; Luke 4:1, 14, 18; Acts 10:38).
Respecting Jesus' role it was necessary that He submit or subject Himself to the Father as a man (John 8:28; Philippians 2:5-8). In this submission, Jesus did not surrender His Divine nature—He was still God. Differing roles or functions, even those requiring submission of one to another, does not deny or diminish equality. We know this is true respecting men and women—spiritual equals before God (Galatians 3:28). Though equals, the woman must submit to her husband and serve in a different role in the Kingdom (1 Timothy 2:11-12; Ephesians 5:22-24). Similarly, the younger are to submit to the elder (1 Peter 5:5), the servant to his master (Colossians 3:22), children submit to parents (Ephesians 6:1-4) and the entire church to the elders (Hebrews 13:7, 17). Submission does not deny or diminish equality.
Respecting the Spirit's role in the Incarnation as the active agent of the Father, there is nothing that diminishes or denies the Deity of either. The fact that the Father worked through the instrumentality of the Holy Spirit does not prove He was not God (e.g., Luke 1:35). The fact that the Son worked through the instrumentality of the Holy Spirit does not prove that He was not God (e.g., Matthew 12:28; Luke 4:14). Each person in the Godhead had a role or function that they fulfilled. While it was possible for any member of the Godhead to do what the others did, it was not within the scope of the plan and purpose of Deity that it should be any other way. Each member of the Godhead fulfilled His role and His function according to their plan.
There is unity in the Godhead. This unity applies to the essence or nature of God—there is only one state of being God. This unity applies to the will and purpose of God—there is perfect agreement between the three persons who are God regarding their eternal purpose and the execution of their plan. This unity applies to their diverse roles in that plan—each one functions in order that their purpose and their will is accomplished and so that they are glorified as the one true and living God.
We may never fully understand all that there is to know about the One God. But, we can surely seek to know what God has revealed about Himself and in particular what God has willed and purposed for each of us to be acceptable in His sight.