Surah Ar-Ra'd Verse 43

وَيَقُولُ الَّذِينَ كَفَرُوا لَسْتَ مُرْسَلًا ۚ قُلْ كَفَىٰ بِاللَّهِ شَهِيدًا بَيْنِي وَبَيْنَكُمْ وَمَنْ عِندَهُ عِلْمُ الْكِتَابِ

Wa yaqoolul lazeena kafaroo lasta mursalaa; qul kafaa billaahi shaheedam bainee wa bainakum wa man 'indahoo 'ilmul Kitaab

Translation / The Meaning

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."