In Chapter 7, Volf discusses issues concerning the oneness of God and the Trinity.
He begins by identifying tawhid (the Islamic concept of God's oneness) as being the key issue for Muslims disputing the Christian view of God. According to Volf, many Muslims do not see the Christian concept of the Trinity as upholding the truth of there being but one God. Thus, he says, they believe that Christians are, at best, worshiping one true God and two idols in addition to God. Says Volf, this is to Muslims shirk, the unforgivable sin of associating other beings with God.
Indeed, Volf writes that many sophisticated Muslim religious scholars suspect that Christians aren’t true monotheists. It is their perception, he suggests, that Christians affirm one God while at the same time insisting that there are three divine Persons, each worthy of worship.
Obedient to the Qur’an, Volf writes, Muslims, it seems, must reject what Christians appear to affirm: that God has a son, that other gods should be joined to God, that God is one of the three divine beings, and that it is appropriate to worship those other beings in addition to God. From this vantage point, he says, it looks as if Christians worship false gods.
Thus, Volf offers this basic rule for Christians as they speak about God with Muslims: “Never divide divine essence.” He states that Christians must not break this rule when talking with Muslims about God as the Holy Trinity.
The Christian creeds and the great Christian teachers, he says, reject dividing the divine essence no less adamantly than Muslims do.
In addition to stating clearly that there is only one “numerically” identical divine essence, Volf writes, Christians should note that the “Persons” are tied and intertwined together in a most intimate manner, more intimate than any relation between creatures could ever be.
In sum, Volf writes with regard to God’s unity...
1. Christians deny what Muslims deny. And together with Muslims they can say there is “no god but God” (Muhammad, 47:19), because the first of the Ten Commandments says, “You shall have no other gods before me” (Exod. 20:3).
2. Together with Muslims, Christians can say, “God is one and only” (Al Ikhlas, 112:1), because Jesus, echoing the Jewish Shema, affirmed that “the Lord our God, the Lord is one” (Mark 12:29).