where did the concept of the trinity come from
Trinity Trinitarian theologians believe that manifestations of the Trinity are made evident from the very beginning of the Bible. Genesis 1:1-3[12] posits God, His Spirit and the "creative word of God"[13][14] together in the initial Genesis creation narrative account. While the Fathers of the Church saw Old Testament elements such as the appearance of three men to Abraham in Book of Genesis, chapter 18, as foreshadowings of the Trinity, it was the New Testament that they saw as a basis for developing the concept of the Trinity. One of the most influential of the New Testament texts seen as implying the teaching of the Trinity was Matthew 28:19, which mandated baptizing "in the name of the Father, and of the Son, and of the Holy Spirit". Another New Testament text pointing to the Trinity was John 1:1-14, in which the inter-relationships of the Triune God are reflected in the gospel author's description of "the Word", again showing the elements of the Triune God and their eternal (always was, always is, and always shall be) existence. (Revelation 1:8) Reflection, proclamation, and dialogue led to the formulation of the doctrine that was felt to correspond to the data in the Bible.[15]
Trimurti The Trimūrti (/trɪˈmʊərti/;[1] Sanskrit: त्रिमूर्तिः trimūrti, "three forms") is the trinity of supreme divinity in Hinduism[2][3][4][5] in which the cosmic functions of creation, maintenance, and destruction are personified as a triad of deities, typically Brahma the creator, Vishnu the preserver, and Shiva the destroyer,[6][7] though individual denominations may vary from that particular line-up. When all three deities of the Trimurti incarnate into a single avatar, the avatar is known as Dattatreya.[8]