The Trinity of Christianity
Christianity is monotheist because we believe in the Trinity. Understanding 3 separate persons being one God is very hard to grasp and impossible to understand. St. Jerome says, "The true profession of the mystery of the Trinity is to own that we do not comprehend it". In trying to describe how God can be 3 persons and still 1 God, we will always fall short because, as limited beings, we cannot comprehend the full definition of God. What we do have is the Word of God. Just as God has made new covenants with Man, each time deepening our relationship with God, so has God made himself more understandable. We base our belief on, among other versus of the Bible, Matthew 28:18, "go and teach all nations, baptizing them in the name of the Father, and of the Son, and of the Holy Ghost". The force of this passage is decisive. That "the Father" and "the Son" are distinct Persons follows from the terms themselves, which are mutually exclusive. The mention of the Holy Spirit in the same series, the names being connected one with the other by the conjunctions "and . . . and" is evidence that we have here a Third Person co-ordinate with the Father and the Son. The phrase "in the name" (eis to onoma) affirms alike the Godhead of the Persons and their unity of nature. The use of the singular, "name," and not the plural, shows that these Three Persons are One Omnipotent God.