فَوَرَبِّ السَّمَآءِ وَالۡاَرۡضِ اِنَّهٗ لَحَقٌّ مِّثۡلَ مَا٘ اَنَّكُمۡ تَنۡطِقُوۡنَࣖ‏

Then by the Lord of the heaven and earth, indeed, it is truth - just as [sure as] it is that you are speaking