Verse 19

قُلْ أَىُّ شَىْءٍ أَكْبَرُ شَهَـٰدَةً قُلِ ٱللَّهُ شَهِيدٌۢ بَيْنِى وَبَيْنَكُمْ وَأُوحِىَ إِلَىَّ هَـٰذَا ٱلْقُرْءَانُ لِأُنذِرَكُم بِهِۦ وَمَنۢ بَلَغَ أَئِنَّكُمْ لَتَشْهَدُونَ أَنَّ مَعَ ٱللَّهِ ءَالِهَةً أُخْرَىٰ قُل لَّآ أَشْهَدُ قُلْ إِنَّمَا هُوَ إِلَـٰهٌ وَٰحِدٌ وَإِنَّنِى بَرِىٓءٌ مِّمَّا تُشْرِكُونَ

Say, what is the greatest as a testimony? Say, God testifies between me and all of you. Furthermore, He has inspired this Quran to me in order to warn you therewith and whoever receives it. Do you indeed testify that there are other gods with God? Say, I do not testify like you; indeed He is one god and I am surely far removed from what you set up as partners for god.