What I like most about his chapter is that he takes a step back from this politically charged question and considers what exactly is being asked. Tenant comes up with three different, more specific questions that may be being asked, and addresses each in turn. I will do the same here. The three questions are:
- Are the English words "God" and the Arabic word "Allah" interchangeable?
- Do the subjects "God is..." and "Allah is..." refer to the same being?
- Are the predicates that Christians and Muslims use to complete these sentences the same (are the specific beliefs about God and Allah the same)?
1. Are the words "God" and the Arabic word "Allah" interchangeable? In the book, Teennant traces the history of the words and shows how (before Muhammed) Christians used the word "Allah" to refer to their God. There are even existing translations of New Testament books that use the word to refer to God. However, the word was never used to translate the proper name of God (the tetragrammaton YHWH). So, by the time Muhammed came onto the scene, Allah was commonly used by both Jews and Christians to refer to their God the same way that we use the word "god" to refer to any diety of any religion in English.
You can make a qualified "yes" in answer to this question speaking from a purely linguistic standpoint as long as you clarify that you are not using the word 'Allah' as a proper name for God. Muhammed moved the meaning of the word in that direction (using it as a proper name) which requires us to explore the next question.
2. Do the subjects of "God is..." and "Allah is..." refer to the same being? Transitioning from the previous question, you might restate the question this way: "Is the 'Allah' of Islam the same as the 'Allah' of pre-Islamic Arabian Christianity?" In this section, Tennent points out that if one is truly a monotheist they have to believe that God is the ONLY deity. If that is the case, then one could say that anyone seeking God can only be seeking the one being.
This gives yet another qualified affirmative. One could say yes, but would have to explain that just because someone is seeking God does not mean they are finding Him. This leads us to the final question.
3. Are the predicates that Christians and Muslims use to complete these sentences the same (are the specific beliefs about God and Allah the same)? Here is where we obtain some clarity. The good news is that a lot of what the Qur'an says about God is in line with the Bible. For example, Christians and Muslims agree that God is the creator (Surah 57:4), that Abraham is a great example of faith (Surah 16:123) that Jesus was born of the virgin Mary (Surah 3:45-47), and that Jesus was without sin (Surah 19:19). However, Christians hold some very central and distinctive beliefs about God that are not in line with Islam; namely, the trinity, the deity of Christ, the diety of the holy spirit, the incarnation of God in Jesus, God in Jesus suffering on the cross, etc.. Likewise, there are several problematic beliefs put forth in the Qur'an like the fact that God is the deceiver who leads people astray.
We can finally come to a well reasoned conclusion. While the word may have been used to refer to the Christian God before the time of Muhammed and while a monotheist cannot believe that there is another god to which a human can direct their worship, one has to say that the being described by Christianity and Islam cannot be the same being as central concepts about that being put forth by each religion lie well outside the bounds of the opposing religion's understanding of that being.
So, no, The God of Muhammed is not the Father of Jesus.
We must be encouraged by this. One of the things we discover when looking at these two religions is that there is a large amount of overlap. That is good news! That means that we can be like the Apostle Paul at Mars Hill (Acts 17:22-34). He surveyed their temple and found a bit of their religion that he could identify as true and used that to open up a conversation about the One True God! May we seek to do the same sort of respectful evangelism in our world!