Al-Ahqaf 46:8

Or do they say, “He has fabricated it”? Say, “If I did fabricate it, there is nothing you can do to protect me against Allah. He knows best that in which you indulge[2]. He is Sufficient as a witness between me and you, and He is the All-Forgiving, the Most Merciful.”

[2] Of false accusations and slander about Qu’ran and Prophet (ﷺ).

Or do they say, "He has invented it"? Say, "If I have invented it, you will not possess for me [the power of protection] from Allāh at all. He is most knowing of that in which you are involved.[1478] Sufficient is He as Witness between me and you, and He is the Forgiving, the Merciful."

[1478] Of false implications and suggestions.

8. Or say they: "He (Muhammad صلى الله عليه وسلم) has fabricated it." Say: "If I have fabricated it? still you have no power to support me against Allâh. He knows best of what you say among yourselves concerning it (i.e. this Qur’ân)! Sufficient is He as a witness between me and you! And He is the Oft-Forgiving, the Most Merciful."

Or say they: He hath invented it? Say (O Muhammad): If I have invented it, still ye have no power to support me against Allah. He is Best Aware of what ye say among yourselves concerning it. He sufficeth for a witness between me and you. And He is the Forgiving, the Merciful.