Trevin Wax: You write in the introduction that many Christians feel unequipped to share the gospel with Muslims. Why do we feel this way? And why should we be confident?

Thabiti Anyabwile: Many Christians seem to accept two myths when it comes to sharing the gospel with Muslims. First, many Christians tend to think every Muslim has memorized the Qur'an and is likely a radical. That's the "super Muslim" myth.

Second, many Christians think they need to be world class apologists, able to answer ever Muslim question or critique of Christianity. That's the "I'm so inadequate" myth.

The result of these two assumptions is that many Christians harbor a lot of fear when it comes to speaking with Muslims. And that fear causes a crisis in confidence—they doubt that the gospel is the power of God unto salvation for everyone who believes. They shrink back, telling themselves that they don't know enough, that their Muslim neighbor is more confident, and that it's probably no use.

The truth, however, is exactly the opposite. If we are Gospel-believing Christians, with even a basic understanding of the "good news," then we know all that we need to know in order to effectively reach our Muslim neighbors and friends. The power of God is not in our wisdom or in our techniques; those things threaten to empty the cross of its power (1 Cor. 1:17).

But the gospel itself, that is the power of God unto salvation for everyone who believes. In the message of Jesus' perfect righteousness, sacrificial death for our sins, glorious resurrection, and second coming in glory, God has placed His power to make sinners new, to raise spiritually dead men to life, to change the hardest human heart into a heart that loves God, to justify us and satisfies His righteous wrath. What we need is confidence in the gospel, for God makes the gospel to triumph in every nation.

Trevin Wax: Why is the doctrine of the Trinity so important in Christian evangelism of Muslims?

Thabiti Anyabwile: The short answer is because John 17:3 tells us that eternal life is to know the only true God and Jesus Christ whom He has sent. John 4:24 says the Father seeks a people who will worship Him in spirit and in truth. An accurate knowledge of God is what makes the difference between idolatry and a genuine personal relationship with God. If we get God wrong, we get everything wrong. So, the fact that God reveals Himself as Triune in nature—one God existing eternally in Three Persons—becomes critical for receiving eternal life.

The slightly longer answer is that each Person in the Trinity plays a significant role in the redemption of sinners. The Father administers our salvation, the Son accomplishes our salvation, and the Spirit applies our salvation (Eph. 1:3-14). If we surrender the biblical doctrine of the Trinity, we surrender the gospel itself.