ٱلْبَقَرَة : ٦

  • إِنَّ Indeed
  • ٱلَّذِينَ those who
  • كَفَرُواْ disbelieve[d]
  • سَوَآءٌ (it) is same
  • عَلَيۡهِمۡ to them
  • ءَأَنذَرۡتَهُمۡ whether you warn them
  • أَمۡ or
  • لَمۡ not
  • تُنذِرۡهُمۡ you warn them
  • لَا not
  • يُؤۡمِنُونَ they believe
Indeed, those who disbelieve1 - it is all the same for them whether you warn them or do not warn them - they will not believe.
Footnotes
1 - Literally, "cover" or "conceal" (faith or truth).
As for the disbelievers, the likes of Aboo Jahl, Aboo Lahab and such; alike it is for them whether you have warned them or have not warned them, they do not believe, as God knows very well, so do not hope that they will believe (read a-andhartahum pronouncing both hamzas, or by not pronouncing the second, making it an alif instead, and inserting an alif between the one not pronounced and the other one, or leaving [this insertion]; al-indhaar ['warning'] is to give knowledge of something, and simultaneously instil an element of fear).