وَيَقولُ الَّذينَ كَفَروا لَستَ مُرسَلًا ۚ قُل كَفىٰ بِاللَّهِ شَهيدًا بَيني وَبَينَكُم وَمَن عِندَهُ عِلمُ الكِتابِ

The unbelievers say, “You are not a Messenger.” Respond, “God suffices as a witness between me and you, along with anyone who has knowledge of the Scripture.”