YAA SIIN — Ayat 10

وَسَوَاء عَلَيْهِمْ أَأَنذَرْتَهُمْ أَمْ لَمْ تُنذِرْهُمْ لاَ يُؤْمِنُونَ

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