“For as I walked around and looked carefully at your objects of worship, I even found an altar with an inscription: TO AN UNKNOWN GOD. So you are ignorant of the very thing you worship – and this is what I am going to proclaim to you” (Acts 17:23)
Timothy George wrote an excellent book exploring the similarities and differences between central Christian and Muslim beliefs, published in 2002, and provocatively entitled Is the Father of Jesus the God of Muhammad? Among other things, George observed that Old Testament Jews were strict monotheists, much like Muslims. Without an explicit concept of the Trinity, prior to the coming of Christ and New Testament revelation, their doctrine of God closely resembled Muslim understanding of Allah. In fact, the etymologies of Allah and El (or Elohim), a common Hebrew name for God in the Old Testament are probably related in pre-Arabic, pre-Hebraic Semitic tongues. Jews who did not become followers of Jesus often stumbled over the very thing Muslims do, the notion of the deity of Jesus or of a Triune God more generally. So perhaps Muslim views of Allah approximate pre-Christian Jewish understandings of Yahweh. Because the New Testament can properly speak of Yahweh, the Lord God of Israel, as Jesus’ father, then maybe the Father of Jesus is the God of Muhammad.
George, however, concludes that this is going too far. The God of the Old Testament was a Triune God from all eternity past, whether most Jews ever realized it or not. There are at least hints of a plurality within the Godhead in the Old Testament in ways there are not in the Qur’an. There is nothing in the Old Testament that unequivocally states that God cannot have a Son, as repeatedly appears in the holy book of Islam. Read both the Jewish Scriptures and the Qur’an and despite the occasional picture of Allah as compassionate, the dominant impression one gets is of an all-powerful, all-knowing being whose mood is almost always one of judgment, primarily on outsiders to Islam. Read the Old Testament—actually read the whole thing and don’t just trust someone else’s simplistic summary—and Yahweh, God of Israel, is predominantly a God of love. When judgment does appear, most of the time it is against God’s own people. The major exception, with the inhabitants of Canaan in the days of Joshua, came only after centuries of God’s patience, until their sins had reached “full measure” (Gen. 15:16).
But one of our readers asks me to address this issue via a slightly different question: Can Allah and God ever be used interchangeably? Here I would agree with many missiologists, especially some who have served in Muslim contexts, that the answer is yes, so long as one goes on to define one’s terms carefully.
That’s exactly what Paul did on Mars Hill. Using theos, the general term for G/god in the Greek language, and based on an inscription to an unknown theos, he proceeded to define the term for the Athenians more accurately. But he never abandoned the term. “God” is an exceedingly common word for God in the Bible! There are plenty of accounts from the history of Christian missions of missionaries insisting on using a foreign word for God, or even creating a new word, in a given language because they cannot accept any indigenous word as close enough in meaning to the God of Scripture. Inevitably, additional barriers have been erected for the acceptance of the Gospel. Now in some instances, this may have been unavoidable, if no term exists that is not inherently polytheistic.
But in Arabic, Allah is as monotheistic as words come. Arabic Christians, before Islam was even birthed in the seventh century, used Allah to translate the biblical words for God. Here is a history we can draw on. Theos, of course, was used by Greek translators of the Septuagint, long before the coming of Christ, despite it being a term very susceptible to polytheistic overtones, but not inherently so.
So it all depends on context. If one can use Allah and explain what one means by it and this is a bridge for sharing Christian beliefs, by all means use it. If among a different group of people, it is inextricable from distinctively Islamic tenets, one may have to abandon it. Great discernment is needed either way.