Surat Al-An'aam (The Cattle) - الأنعام

قُلْ أَىُّ شَىْءٍ أَكْبَرُ شَهَٰدَةً قُلِ ٱللَّهُ شَهِيدٌۢ بَيْنِى وَبَيْنَكُمْ وَأُوحِىَ إِلَىَّ هَٰذَا ٱلْقُرْءَانُ لِأُنذِرَكُم بِهِۦ وَمَنۢ بَلَغَ أَئِنَّكُمْ لَتَشْهَدُونَ أَنَّ مَعَ ٱللَّهِ ءَالِهَةً أُخْرَىٰ قُل لَّآ أَشْهَدُ قُلْ إِنَّمَا هُوَ إِلَٰهٌ وَٰحِدٌ وَإِنَّنِى بَرِىٓءٌ مِّمَّا تُشْرِكُونَ ﴿١٩﴾

Say: What thing is the weightiest in testimony? Say: Allah is witness between you and me; and this Quran has been revealed to me that with it I may warn you and whomsoever it reaches. Do you really bear witness that there are other gods with Allah? Say: I do not bear witness. Say: He is only one Allah, and surely I am clear of that which you set up (with Him).