We are taught in scripture that the one who denies that Jesus is the son of God is of the Antichrist spirit.
1 John 2:22
Who is the liar? It is whoever denies that Jesus is the Christ. Such a person is the antichrist–denying the Father and the Son.
You see, if you deny the son, then you have to deny that God is a Father also.
Islam for example blatantly proclaims that Allah (God) has no son. This would by biblical standards make that of the Antichrist spirit. A God that does not have a son cannot be the God spoken of in scripture.
But denying the Father and the Son is not always so blatant. There are deceptive doctrines in the Church that subtly deny the Father and the Son. One such doctrine is the Trinity. This doctrine teaches that Jesus is God himself and one of three members that make up a triune God. Yet scripture is adamant, there is but one God the Father and the Jews who were given the Old Testament have never believed in the Trinity and have never been rebuked for not believing in the Trinity.
1 Corinthians 8:6
yet for us there is but one God, the Father, from whom all things came and for whom we live; and there is but one Lord, Jesus Christ, through whom all things came and through whom we live.
One Lord, one faith, one baptism, One God and Father of all, who is above all, and through all, and in you all.
But how does the Trinity deny the Father and the Son?
If you say that Jesus is God, then clearly you are denying that he is the image of that God. An image cannot be the source and God is not an image.
The Son is the image of the invisible God, the firstborn over all creation.
If you say that Jesus is God, then clearly you are denying that God made Jesus Lord and Messiah.
“Therefore let all Israel be assured of this: God has made this Jesus, whom you crucified, both Lord and Messiah.”
If you say that Jesus is God, then indeed you are denying that he is the son of that God.
For God did not send his Son into the world to condemn the world, but to save the world through him.
Unless Jesus is the son of himself (God) he cannot be God. Clearly he is the son of the one true God. Any doctrine or religion that denies that he is the son of God whether in word or deed, is of the Antichrist spirit according to the Apostle John.
We need to be careful as to what we believe. We need to check all things out to see if they are true. We should never accept teachings without first testing them. We test them using the scriptures and the guidance of God’s Holy Spirit.
Listen to the words of eternal life from Jesus himself. Read them carefully. Do you believe these words to be true? If so, you cannot hold to the Doctrine of the Trinity.
Now this is eternal life: that they know you, the only true God, and Jesus Christ, whom you have sent.
God is often spoken of as HIM and HE, never THEY or THEM as would be grammatically correct if we held to the Trinity Doctrine.
There is one true God, the Father, and one whom he made Lord, the Lord Jesus Christ. God made him the messiah, and he is the only begotten son of God. It is through the son of God that we can have fellowship with God himself.