Sura al-Anʿām 6:19

قُلْ أَىُّ شَىْءٍ أَكْبَرُ شَهَٰدَةً قُلِ ٱللَّـهُ شَهِيدٌۢ بَيْنِى وَبَيْنَكُمْ وَأُوحِىَ إِلَىَّ هَٰذَا ٱلْقُرْءَانُ لِأُنذِرَكُم بِهِۦ وَمَنۢ بَلَغَ أَئِنَّكُمْ لَتَشْهَدُونَ أَنَّ مَعَ ٱللَّـهِ ءَالِهَةً أُخْرَىٰ قُل لَّآ أَشْهَدُ قُلْ إِنَّمَا هُوَ إِلَٰهٌ وَٰحِدٌ وَإِنَّنِى بَرِىٓءٌ مِّمَّا تُشْرِكُونَ

qul ayyu shayʾin akbaru shahādatan quli allāhu shahīdun baynī wa-baynakum wa-ūḥiya ilayya hādhā l-qurʾānu li-undhirakum bihi wa-man balagha a-innakum la-tashhadūna annā maʿa allāhi ālihatan ukhrā qul lā ashhadu qul innamā huwa ilāhun wāḥidun wa-innanī barīʾun mimmā tushrikūna

Say: "What thing is most weighty in evidence?" Say: "Allah is witness between me and you; This Qur'an hath been revealed to me by inspiration, that I may warn you and all whom it reaches. Can ye possibly bear witness that besides Allah there is another Allah?" Say: "Nay! I cannot bear witness!" Say: "But in truth He is the one Allah, and I truly am innocent of (your blasphemy of) joining others with Him."