And it is all the same for them whether you warn them or do not warn them - they will not believe.

وَسَوَاءٌ عَلَيْهِمْ أَأَنْذَرْتَهُمْ أَمْ لَمْ تُنْذِرْهُمْ لَا يُؤْمِنُونَ