Why don't Apostolic churches believe in the Trinity and what scriptures do they base this on?

Apostolic churches, particularly those associated with Oneness Pentecostalism, reject the traditional doctrine of the Trinity, believing instead in the oneness of God, where Jesus Christ is seen as the singular manifestation of the one God. They often cite scriptures such as John 10:30, where Jesus says, "I and the Father are one," and Deuteronomy 6:4, which states, "Hear, O Israel: The Lord our God, the Lord is one." They emphasize a belief in the absolute unity of God rather than a triune nature. This theological stance leads them to interpret the roles of the Father, Son, and Holy Spirit as different manifestations of the same divine person rather than distinct persons within the Godhead.