وَكَذَلِكَ حَقَّتْ كَلِمَةُ رَبِّكَ عَلَى الَّذِينَ كَفَرُواْ أَنَّهُمْ أَصْحَـبُ النَّارِ
(Thus has the Word of your Lord been justified against those who disbelieved, that they will be the dwellers of the Fire.) means, `just as the Word of punishment was justified against those of the past nations who disbelieved, so too is it justified against these disbelievers who have rejected you and gone against you, O Muhammad, and it is even more justified against them, because if they have disbelieved in you, there is no certainty that they will believe in any other Prophet.' And Allah knows best.