Trinity [Lat.,=threefoldness], fundamental doctrine in Christianity, by which God is considered as existing in three persons. While the doctrine is not explicitly taught in the New Testament, early Christian communities testified to a perception that Jesus was God in the flesh; the idea of the Trinity has been inferred from the Gospel of St. John. The developed doctrine of the Trinity purports that God exists in three coequal and coeternal elements—God the Father, God the Son, and God the Holy Spirit (see creed 1). It sees these "persons" as constituted by their mutual relations, yet does not mean that God in his essence is Father, or a male deity. Jesus spoke of a relation of mutual giving and love with the Father, which believers could also enjoy through the Spirit. The Trinity is commemorated liturgically in the Western Church on Trinity Sunday. For systems denying the Trinity, see Unitarianism.