QUESTION: Do people of other religions worship the same God as Christians?
WARREN: Of course not. Christians have a view of God that is unique. We believe Jesus is God! We believe God is a Trinity: Father, Son, and Holy Spirit. Not 3 separate gods but one God. No other faith believes Jesus is God. My God is Jesus. The belief in God as a Trinity is the foundational difference between Christians and everyone else. There are 2.1 billion people who call themselves Christians... whether Catholic, Orthodox, Protestant, Pentecostal, or Evangelical... and they all have the doctrine of the Trinity in common. Hindus, Muslims, Jehovah's Witnesses, Christian Science, Unitarians, and everyone else do not accept what Jesus taught about the Trinity.
Since both Islam and Christianity are monotheistic, what would be wrong with claiming that Christians and Muslims worship the "same" God?
There are two reasons why we should refrain from agreeing to this claim: respect for truth and respect for the freedom of religious belief.
The first, and most important, reason is that Islam denies a fundamental truth that is necessary for the claim that Christians and Muslims worship the "same" God to be true. One of the basic axiomatic truths of Christianity is that God is Triune. While this can be a difficult doctrine to understand, almost all Christians would agree that Jesus is not a "part" or "attribute" of God but is one of three persons in the Trinity. A Christian cannot speak of "God" without including Christ.
When we claim that we worship the "same" God we are essentially saying that Jews and Muslims worship Christ but they just don't know it. By taking this position we are either denying the validity of our belief in Christ or dismissing the Muslims' belief that Jesus is not divine. In essence we are claiming either that (1) despite their denials to the contrary, Muslims recognize Jesus is God, or (2) that it is possible to know and worship God and yet deny that Christ is God.