Surah Al-Ahqaf (The Sand-Hills), Verse 8

اَمْ یَقُوْلُوْنَ افْتَرٰىهُ قُلْ اِنِ افْتَرَیْتُهٗ فَلَا تَمْلِكُوْنَ لِیْ مِنَ اللّٰهِ شَیْـًٔا هُوَ اَعْلَمُ بِمَا تُفِیْضُوْنَ فِیْهِ كَفٰی بِهٖ شَهِیْدًا بَیْنِیْ وَبَیْنَكُمْ وَهُوَ الْغَفُوْرُ الرَّحِیْمُ ۟

Am yaqooloonaf taraahu qul inif taraituhoo falaa tamlikoona lee minal laahi shai'an Huwa a'lamu bimaa tufeedoona feehi kafaa bihee shaheedam bainee wa bainakum wa Huwal Ghafoorur Raheem

“Or do they say, "He has forged it"? Say: "Had I forged it, then can ye obtain no single (blessing) for me from Allah. He knows best of that whereof ye talk (so glibly)! Enough is He for a witness between me and you! And he is Oft-Forgiving, Most Merciful."”

Quran 46:8 (Yusuf Ali Translation)