Verse 43

وَيَقُولُ ٱلَّذِينَ كَفَرُوا۟ لَسْتَ مُرْسَلًا قُلْ كَفَىٰ بِٱللَّهِ شَهِيدًۢا بَيْنِى وَبَيْنَكُمْ وَمَنْ عِندَهُۥ عِلْمُ ٱلْكِتَـٰبِ

And the unfaithful say; you are not a messenger. Say, God suffices as a witness between me and you and those who possess knowledge of the scripture.