intellectual defeat of disbelievers

ثُمَّ نُكِسُوا۟ عَلَىٰ رُءُوسِهِمْ لَقَدْ عَلِمْتَ مَا هَـٰٓؤُلَآءِ يَنطِقُونَ

Then they reversed themselves, [saying], "You have already known that these do not speak!"