Trinity

The Trinity is the doctrine that, in the unity of the One God, there are three divine persons: the Father, Son, and Spirit, distinct from one another yet of one substance. The three persons are co-eternal and uncreated: "the Father is God, the Son is God, and the Holy Spirit is God, and yet there are not three Gods but one God." Jesus is understood by Trinitarian Christians to be the person of the Son, eternally begotten by the Father, who came upon earth to deliver to the world.
Such language appears in Matthew 28:19, "Therefore go and make disciples of all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit." This was incorporated into baptismal formulae, which also invoked a renunciation of Satan, contrasting the initiate's belief in the One God with the idolatry of polytheistic paganism. This language also appears in early doxologies (Galatians 5:25; Romans 8:9; Hebrews 13:15)[34] The doctrine found full articulation with the Council of Nicaea.