Qur'an 4:171

يَـٰٓأَهْلَ ٱلْكِتَـٰبِ لَا تَغْلُوا۟ فِى دِينِكُمْ وَلَا تَقُولُوا۟ عَلَى ٱللَّهِ إِلَّا ٱلْحَقَّ ۚ إِنَّمَا ٱلْمَسِيحُ عِيسَى ٱبْنُ مَرْيَمَ رَسُولُ ٱللَّهِ وَكَلِمَتُهُۥٓ أَلْقَىٰهَآ إِلَىٰ مَرْيَمَ وَرُوحٌ مِّنْهُ ۖ فَـَٔامِنُوا۟ بِٱللَّهِ وَرُسُلِهِۦ ۖ وَلَا تَقُولُوا۟ ثَلَـٰثَةٌ ۚ ٱنتَهُوا۟ خَيْرًا لَّكُمْ ۚ إِنَّمَا ٱللَّهُ إِلَـٰهٌ وَٰحِدٌ ۖ سُبْحَـٰنَهُۥٓ أَن يَكُونَ لَهُۥ وَلَدٌ ۘ لَّهُۥ مَا فِى ٱلسَّمَـٰوَٰتِ وَمَا فِى ٱلْأَرْضِ ۗ وَكَفَىٰ بِٱللَّهِ وَكِيلًا

“O People of the Scripture, do not commit excess in your religion or say about Allāh except the truth. The Messiah, Jesus the son of Mary, was but a messenger of Allāh and His word which He directed to Mary and a soul [created at a command] from Him. So believe in Allāh and His messengers. And do not say, "Three"; desist - it is better for you. Indeed, Allāh 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 Allāh as Disposer of affairs.”

An-Nisaa 4:171 · Saheeh International