“… an angel of the Lord appeared to him in a dream, saying, ‘Joseph, son of David, do not be afraid to take Mary as your wife; for the Child who has been conceived in her is of the Holy Spirit.” Matthew 1:20
The Christ child was not conceived “of” Joseph or “of” some other man, as baby Jesus was supernaturally “conceived” in Mary “of the Holy Spirit.”
“There is one body and one Spirit, just as also you were called in one hope of your calling; one Lord, one faith, one baptism, one God and Father of all who is over all and through all and in all.” Ephesians 4:4-6
Notice that the “One Spirit” of “One Lord” is that Spirit of the “One God and Father of all who is above all and through all and in all.” Hence, the Holy Spirit is the same Spirit of the only true God the Father (John 17:3) who became the Christ child in the virgin. “…for the Child who has been conceived in her is of the Holy Spirit.” Matthew 1:20
Hebrews 1:3, “Who being the brightness of His glory, and the express image (Greek – Charakter ‘imprint’ or ‘reproduced copy’) of His person (Greek – Hypostasis ‘substance of Being or Person’) …”
When God the Father’s Holy Spirit became a man through the virgin in the incarnation, His “substance of Being” (hypostasis – Heb. 1:3) was “reproduced” (charakter – Heb. 1:3) in order to be united with a fully complete human nature as one person called the Messiah with only one personality, not two. True Oneness Theology does not teach that Jesus is the Father and the Son as two personalities living in one body side by side with each other. Oneness apologist Jason Dulle and I have pointed out that Jesus could not have existed with two personalities as the Father and the Son living side by side (having a divine side and a human side) because the One true God did not become half God and half a man in the incarnation. God clearly became “fully human in every way” (Heb. 2:17) in the incarnation with one human personality, not two. Therefore the omnipresent Father also became a true man through the virgin with a human spirit, a human mind, a human will, and a human body.
Oneness apologist Jason Dulle wrote Under “Avoiding the Archiles Heel of Trinitarianism ... Nestorianism ... (at onenesspentecostal.com),”
“The internalist model turns Jesus into two beings residing in one body, like roommates sharing an apartment. If the distinction between Father and Son is a distinction between Jesus' divine and human natures, then when Jesus spoke He should have referred to ‘us’ and ‘we,’ not ‘I’ and ‘me.’ Jesus never spoke in such terms, however, because He was one person with one center of consciousness. Natures do not speak, pray, heal, and teach—people do.”
Wherefore, Jesus Christ of Nazareth did not sometimes speak as the Father and at other times speak as the Son; as that would be a Messiah as two persons with a divine and a human consciousness. For one person as one person cannot speak with more than one consciousness. Hence, Jesus Christ as God with us as a true man clearly spoke with only one human consciousness because he had a divine awareness of his true identity as “God with us” as a man which came by revelation from his Father.
I am 100% in agreement with Oneness apologist Jason Dulle who wrote that “Splitting Christ in Two” is a Nestorian error which dismantles Christ's true identity as God who became a true man in the incarnation. Jason Dulle further wrote in his article, “The Archiles Heel of Trinitarianism … Nestorianism,”
“It would be impossible for some of Christ’s actions to be those of a man and some to be those of God, for such a notion posits two persons in Christ: one who is God and one who is man. This is impossible in light of a true incarnation of God. Jesus is God Himself existing as man, not God and a man existing together in one geographical locale; not a divine person and a human person coexisting side-by-side. Because Jesus is God’s human mode of existence, there must of necessity be only one personal subject in Christ—not two—and that one personal subject is God.”
Jason Dulle went on to write, “In contrast to Jesus who is God existing as man, we are man existing as man. Just as we are the subject of all our actions, likewise God is the subject of all Christ’s actions. God is the one who experienced sleep, hunger, thirst, and pain. Christ's humanity is God's humanity by virtue of the incarnational act wherein He Himself became man, and thus all of Christ's acts are those of God Himself in genuine human existence. Jesus, therefore, is not God acting and knowing as God and man acting and knowing as man side-by-side one another, but God acting and knowing as man through His human mode of existence (Jason Dulle, “The Archiles Heel of Trinitarianism … Nestorianism”, onenesspentecostal.com).”
The man Christ Jesus could not have sometimes spoke as God and at other times spoke as a Son because the One true God also became one true man in the incarnation through the virgin. This explains why Mark 13:32 informs us that the man Christ Jesus did not know the day and the hour of his own second coming, “but the Father alone.” Jesus is God’s mode of existence as a fully complete man who could pray and be tempted as a man inside the incarnation who did not know all things. In contradistinction, the omnipresent Heavenly Father who could not pray or be tempted as the All-Knowing God outside of the incarnation was also able to simultaneously exist in the incarnation as a true man, Jesus our Messiah.
The Nestorian view undermines the scriptural understanding that Jesus is “Immanuel,” “God with us” as a true man in the incarnation through the virgin. For the Messiah could not have been two persons living side by side as one divine and one human person coexisting in one physical body. True Oneness Theology rejects the idea that Jesus had a divine side and a human side as two personalities within his being. For just as no true man can exist as two persons within one body, so the only true God also became a true man via virgin conception and birth.
Hebrews 2:14 (NIV) says, “Since the children have flesh and blood, he too shared in their humanity so that by his death he might break the power of him who holds the power of death—that is, the devil.”
Hebrews 2:14-17 proves that the God who partook of flesh and blood in order to share in our humanity was also made like all men, “fully human in every way.”
“For this reason he had to be made like them, fully human in every way …” Heb. 2:17 NIV
Oneness Theology rejects any idea that Jesus Christ is anything other than God who became a true man in the incarnation with a fully complete human spirit, a fully complete human will, and a fully complete human body. Therefore God as man in the incarnation has only one human will while God as God outside of the incarnation has only one divine will as our Heavenly Father.