The divine lordship and the deity of Jesus Christ were denied in the fourth century by a man named Arius. He was sincere. He was well read. He did not deny that the Bible was true. But he said, Jesus Christ is a creature. He's higher than any other creature. But he is not God. Arius denied that Jesus was the same essence, the same fundamental reality, as God. At the Council of Nicea, the church had to say, No, we can't go that way either. The one we adore and worship and love in Jesus our Redeemer is of the same essence as the Father. We're not talking about two different gods. We're talking about the one God, but the one God who has forever known himself as Father, Son, and Holy Spirit. This says to us that the fundamental reality of God is relationship—it's community. If we can ever grasp that, we'll understand what our fundamental differences are with Islam.
The third central Christian affirmation is that the Holy Spirit is personal. This affirmation also has had a divisive history. About 70 years after the Council of Nicea, some people said they would go along with God the Father and God the Son, but they could not affirm that the Holy Spirit is God—that was just too much for them. They claimed that the Holy Spirit is a force, an energy, a power, but not God. Over against these people, who were known as the Spirit-fighters (because they fought against the deity of the Holy Spirit), the church declared that God is one in essence, and three in person—Father, Son, and Holy Spirit.
God was in Christ, reaching out to us in love, accommodating himself to our condition, to save us.
So many believes, all at the same time...!!!