Verse 19

وَمَا كَانَ ٱلنَّاسُ إِلَّآ أُمَّةً وَٰحِدَةً فَٱخْتَلَفُوا۟ وَلَوْلَا كَلِمَةٌ سَبَقَتْ مِن رَّبِّكَ لَقُضِىَ بَيْنَهُمْ فِيمَا فِيهِ يَخْتَلِفُونَ

And the people used to be one single community but they disputed. If it were not for a preordained word from your Lord, they would have indeed been judged regarding their disputes.