The Christian doctrine of the Trinity defines God as three divine persons or hypostases: the Father, the Son, and the Holy Spirit; “one God in three persons”. The three persons are distinct, yet are one “substance, essence or nature”. A nature is what one is, while a person is who one is. The Trinity is considered to be a mystery of Christian faith. According to this doctrine, there is only one God in three persons. Each person is God, whole and entire.