Caution: Translations of Quran and Ḥadīth may lead to possible misapplications and misinterpretations. This site is intended for students of sacred knowledge that are proficient in comprehending classical Arabic and have a strong foundation in Islamic sciences. Also note that religious injunctions rely on several aspects beyond what one may glean through reading individual aḥādīth.
quran:5:73

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.  

They are indeed disbelievers those who say, ‘God is the third of three’, gods, that is, He is one of them, the other two being Jesus and his mother, and they ˹who claim this˺ are a Christian sect; when there is no god but the One God. If they do not desist from what they say, when they declare a trinity, and profess His Oneness, those of them who disbelieve, that is, ˹those˺ who are fixed upon unbelief, shall suffer a painful chastisement, namely, the Fire.
القرآن:٥:٧٣

لَقَدْ كَفَرَ الَّذِينَ قَالُوا إِنَّ اللَّهَ ثَالِثُ ثَلَاثَةٍ ۘ وَمَا مِنْ إِلَٰهٍ إِلَّا إِلَٰهٌ وَاحِدٌ ۚ وَإِنْ لَمْ يَنْتَهُوا عَمَّا يَقُولُونَ لَيَمَسَّنَّ الَّذِينَ كَفَرُوا مِنْهُمْ عَذَابٌ أَلِيمٌ  

{لقد كفر الذين قالوا إن الله ثالث} آلهة {ثلاثة} أي أحدها والآخران عيس وأمه وهم فرقة من النصارى {وما من إله إلا إله واحد وإن لم ينتهوا عما يقولون} من التثليث ويوحدوا {ليمسنَّ الذين كفروا} أي ثبتوا على الكفر {منهم عذاب أليم} مؤلم وهو النار.