Ya-Sin - 36:10

وَسَوَاء عَلَيْهِمْ أَأَنذَرْتَهُمْ أَمْ لَمْ تُنذِرْهُمْ لاَ يُؤْمِنُونَ
[36:10]
And it is alike to them whether you warn them or warn them not: they do not believe.
The same is it to them whether thou admonish them or thou do not admonish them: they will not believe.
Whether thou warn them or thou warn them not, it is alike for them, for they believe not.