Surah Yasin Tafseer

It is the same to them whether you warn them or you warn them not, they will not believe.

means, Allah has decreed that they will be misguided, so warning them will not help them and will not have any effect on them. Something similar has already been seen at the beginning of Surah Al-Baqarah,

and Allah also says:

إِنَّ الَّذِينَ حَقَّتْ عَلَيْهِمْ كَلِمَةُ رَبِّكَ لَا يُوْمِنُونَ

وَلَوْ جَأءَتْهُمْ كُلُّ ءايَةٍ حَتَّى يَرَوُاْ الْعَذَابَ الاٌّلِيمَ

Truly, those, against whom the Word (wrath) of your Lord has been justified, will not believe, Even if every sign should come to them, until they see the painful torment. (10:96-97