This is the common perception among some non-Christian sects concerning the doctrine of the Trinity. First, that Christians believe in the one God. They are not polytheists or infidels as some who do not comprehend the essence of this doctrine and its content like to accuse them. Secondly, Christianity strongly rejects any belief in the polytheism. This has been the traditional attitude of the Christian church since its inception and up to the present time.
Any sect believing in the existence of three gods is heretical.
Anyone who examines the Scriptures will never find any claim of polytheism because it is against the law of the Holy God. Christ's apostles emphasized the oneness of God. Therefore, the church, in order to avoid any kind of misunderstanding, formulated this doctrine as the canon of the Christian faith. It is necessary before discussing the concept of the Triune God to allude to some of its phenomenon as they are transpired in the New Testament. Before the ascension of the Lord Jesus Christ to heaven, he addressed his disciples and commissioned them to go and preach the gospel to all nations and baptize them in the name of the Father and the Son and the Holy Spirit .