Surely Allah does not forgive shirk (associating any partner with Him); and may forgive sins other than that if He so pleases. This is because one who commits shirk with Allah, does indeed invent a great sinful lie. (Surah 4:48, F. Malik Translation)
One of the greatest stumbling blocks to communicating the gospel of grace to the Muslim is “designed into the system” itself through the fact that Mohammed did not understand the Christian doctrine of the Trinity. Muslims today believe the Christian doctrine of the Trinity is actually a form of tri-theism, a belief in three gods, not the deeply, fundamentally monotheistic belief it truly is. As such, whenever they see Christians worshipping Christ, or speaking of Him as the Son of God, or using the word “Trinity,” they automatically think of the most heinous and high sin of shirk, for they have been taught that Christians are in some sense “adding” partners to God in the person of Christ, who was, they have been told, a mere creature.
Imagine for a moment how effective this roadblock truly is. From the point of your earliest memories you have been told that the Trinity is tri-theistic, and that to worship in such a fashion is to commit the most horrible and unforgivable sin imaginable! And so when that Christian missionary speaks to you about “the Lord Jesus Christ” all you can hear is “idolatry, IDOLATRY, SHIRK!!!” I saw this with startling clarity in the debate in 1999 against Hamza Abdul Malik: there was a wall between me and the Muslims in the audience. As soon as I would open my mouth to answer a question, you could see the head start to shake, the mind already closed. Jesus can’t be God. No amount of Scripture could change their mind. Elsewhere (Surah 4:171) the Qur’an states:
So believe in Allah and His Rasools and do not say: “Trinity”.” Stop saying that, it is better for you. Allah is only One Deity. He is far above from the need of having a son!
One of the greatest evidences of the fact that the Qur’an is not inspired Scripture is the fact that its author did not understand a doctrine that had already been fully defined at the time of its writing. We will look more closely at what the Qur’an describes as the “Trinity” in later installments, but for now it is vital to recognize that there has never been a time in Christian history when Christians have not asserted with the full force of orthodoxy the absolute truth of monotheism. There is only one true God. The Trinity is not setting up “equals” or “partners” with the one true God. God is “one” on the level of being: there is only “One Deity.” But Islam steps back from the revelation of the Christian Scriptures and joins the Jews of Jesus’ day who could not accept that Yahweh had entered into His own creation in the person of His Son to bring glory to Himself through the redemption of His people. As Jesus said to them then, we must say to Muslims today:
Therefore I said to you that you will die in your sins; for unless you believe that I am He, you will die in your sins (John 8:24).
It is not that God “needs” a Son, as the Qur’an mistakenly says. It is that God has eternally existed as Father, Son, and Holy Spirit, and to deny this revelation of God by accepting a lesser view of God that comes from a later self-proclaimed Scripture is to dishonor the testimony God has given of the Son.