The Thunder
وَيَقُولُ ٱلَّذِينَ كَفَرُوا۟ لَسْتَ مُرْسَلًا ۚ قُلْ كَفَىٰ بِٱللَّهِ شَهِيدًۢا بَيْنِى وَبَيْنَكُمْ وَمَنْ عِندَهُۥ عِلْمُ ٱلْكِتَـٰبِ
And those who have disbelieved say, "You are not a messenger." Say, [O Muhammad], "Sufficient is Allah as Witness between me and you, and [the witness of] whoever has knowledge of the Scripture."
Nearby ayahs help place verse 13:43 in sequence and meaning.
أَوَلَمْ يَرَوْا۟ أَنَّا نَأْتِى ٱلْأَرْضَ نَنقُصُهَا مِنْ أَطْرَافِهَا ۚ وَٱللَّهُ يَحْكُمُ لَا مُعَقِّبَ لِحُكْمِهِۦ ۚ وَهُوَ سَرِيعُ ٱلْحِسَابِ
Have they not seen that We set upon the land, reducing it from its borders? And Allah decides; there is no adjuster of His decision. And He is swift in account.
وَقَدْ مَكَرَ ٱلَّذِينَ مِن قَبْلِهِمْ فَلِلَّهِ ٱلْمَكْرُ جَمِيعًا ۖ يَعْلَمُ مَا تَكْسِبُ كُلُّ نَفْسٍ ۗ وَسَيَعْلَمُ ٱلْكُفَّـٰرُ لِمَنْ عُقْبَى ٱلدَّارِ
And those before them had plotted, but to Allah belongs the plan entirely. He knows what every soul earns, and the disbelievers will know for whom is the final home.