Christianity, like all monotheistic religions, asserts that there is only one God. We do not believe in three Gods. However, Christianity is unique in our understanding that the one God exists in three eternal and personal distinctions known as Father, Son, and Holy Spirit. The church has used the word “Trinity” to capture this great mystery. The word “Trinity” is a combination of two words, “Tri” and “unity.” The “tri” refers to the three eternal distinctions; the “unity” is to reinforce that we believe in only one God. This is normally expressed by saying that we believe that God is one in essence, but reveals himself through three eternal personal distinctions known as Father, Son, and Holy Spirit.
The purpose of this revelation is primarily to demonstrate the personal, relational nature of God. God is, even apart from creation, eternally personal and relational. As the Puritans once observed, “God is, in himself, a sweet society.” There is relationship in the very nature of who God is. The whole universe flows forth from an eternal, relational tri-unity, not from a non-relational, solitary figure as taught by Islam.