The Bible describes the birth of Jesus Christ as follows:
Now the birth of Jesus Christ took place in this way. When his mother Mary had been betrothed to Joseph, before they came together she was found to be with child from the Holy Spirit. (Matthew 1:18 ESV)
Some who deny the doctrine of the Trinity argue that if God the Father is Jesus' Father, why does Scripture state that Mary was pregnant by the Holy Spirit? This question often stems from a misunderstanding or rejection of Jesus' preexistence as God the Son.
The core issue lies in their presupposition that Jesus did not exist before His incarnation. However, the Bible clearly teaches that Jesus, as the eternal Son, existed with God the Father from eternity past. John’s Gospel affirms this:
In the beginning was the Word, and the Word was with God, and the Word was God. He was in the beginning with God. (John 1:1-2 ESV)
This passage establishes that Jesus, the Word, was eternally with the Father and was Himself God. The doctrine of the Trinity holds that God exists as three persons—Father, Son, and Holy Spirit—yet one in essence. Thus, the Holy Spirit’s role in Mary’s conception does not negate the Father’s role as Jesus’ eternal Father. Instead, the Holy Spirit facilitated the incarnation, enabling the eternal Son to take on human flesh.
In summary, the Trinity deniers’ argument overlooks the eternal preexistence of Jesus as God the Son. The Holy Spirit’s action in the incarnation does not contradict the Father’s relationship with the Son but rather fulfills the divine plan for the Word to become flesh (John 1:14).