﴿ قُلْ أَرَءَيْتُمْ إِن كَانَ مِنْ عِندِ ٱللَّهِ ثُمَّ كَفَرْتُم بِهِۦ مَنْ أَضَلُّ مِمَّنْ هُوَ فِى شِقَاقٍۭ بَعِيدٍۢ ﴾

“HAVE YOU given thought [to how you will fare] if this be truly [a revelation] from God, the while you deny its truth? Who could be more astray than one who places himself [so] deeply in the wrong?”

Say ‘Consider this if it the Qur’ān is from God as the Prophet says and you disbelieve in it who — in other words none — will be further astray than one who is in extreme defiance?’ of the truth this third person singular address is used instead of ‘who will be further astray than you’ in order to point out their status as disbelievers.