Hello,
I would say that this is a common error that Many Christians fall into and propagate between each other as a fact. While they have not read the Quran themselves.
Let me make it more clear… the Quran doesn’t define the trinity… at all… the Quran mentions what should not be worshiped . The verse that confuses people is below
quran.com/5/116
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 ?’” He will say, "Exalted are You! It was not for me to say that to which I have no right. If I had said it, You would have known it. You know what is within myself, and I do not know what is within Yourself. Indeed, it is You who is Knower of the unseen.
Now that verse doesn’t include any trinity… but it says that Jesus and Mary could have been regarded as deities as well as God . In Islam … the definition of a deity or a god is broader. If you lift your hands in the air and say ‘’ o Mary bless me with food and shelter’’ then you are taking her as a deity or as a God . This has nothing to do with being a part of a trinity or not . In Islam there is one God who is worthy of supplication, prayer or worship… the rest are humans … including Mary and Jesus.
The Quran is not concerned with defining trinity… it is concerned with showing muslims what is wrong .
quran.com/4/171
O People of the Scripture, do not commit excess in your religion or say about Allah except the truth. 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.
Now you see from the previous verse… There is no definition of the trinity either… basically God is saying…’’ Don’t say Three’’ He is saying there is nothing called the trinity… There is one God and the rest are creatures … including the holy spirit and Jesus, Mary etc…
I have brought you the concerned verses from the Quran itself… you can se there is no definition of the trinity there . In fact… the word trinity is not mentioned…
I hope that would just stop this popular myth.
Best regards,