Islam teaches that the Qur’an is the perfect revelation of Allah, but that presents a problem for Muslims then when it gets things wrong. One of the more notable errors is found in its explanation of what Christians believe about the Trinity. It makes two clear mistakes, first describing us as worshipping three gods. As we read in the fourth and fifth surahs:
.…The Messiah, Jesus, the son of Mary, was but a messenger of Allah and His word which He directed to Mary and a soul [created at a command] from Him. So believe in Allah and His messengers. And do not say, “Three”; desist – it is better for you. Indeed, Allah is but one God. Exalted is He above having a son. To Him belongs whatever is in the heavens and whatever is on the earth. And sufficient is Allah as Disposer of affairs. (4:171)
They have certainly disbelieved who say, “Allah is the third of three.” And there is no god except one God. And if they do not desist from what they are saying, there will surely afflict the disbelievers among them a painful punishment. (5:73)
Secondly, the Qur’an describes Christians as believing in a Trinity made up of the Father, Jesus, and Mary.
And [beware the Day] when Allah will say, “O Jesus, Son of Mary, did you say to the people, ‘Take me and my mother as deities besides Allah?'”…. (5:116)
As you might expect, Muslims do have their explanations for these verses. In some translations they change 5:73’s “…third of three” to say “…one of three in a Trinity” to correct the original error. And they do the same with the “three” in Surah 4:171, changing it to “Trinity.” But as Luke Wayne, of the Christian Apologetics & Research Ministry, notes in his article “Did the author of the Quran understand the Trinity?” that’s not how the earliest Islamic scholars understood these passages:
Muqatil ibn Sulayman’s mid-eighth-century tafsir is considered by scholars to be the earliest complete commentary on the Quran to have survived in good condition. In it, Sulayman claims that Christians “say that Allah, powerful and exalted, is the third of three – he is a god, [Jesus] is a god, and [Mary] is a god, making Allah weak.”
To explain away the error in 5:116 the suggestion is made that Allah, rather than addressing Christians here, was addressing some obscure sect that worshipped a Trinity made up of the Father, Son, and Mary. Or some will point to how Catholics are elevating Mary to an almost god-like status. That is the best they can do.
As Wayne concludes:
It is not hard to understand how a pagan Arab might make these kinds of mistakes based on second-hand stories, hearsay, and uninformed observations and thus end up with the Quran’s erroneous conception of Christian belief. But to say that God Himself might get so confused as to what Christians believe is ludicrous.