Surah Al-Qasas 28:49
ﲨ ﲩ ﲪ ﲫ ﲬ ﲭ ﲮ ﲯ ﲰ ﲱ ﲲ ﲳ ﲴ
Say, "Then bring a scripture from Allah which is more guiding than either of them that I may follow it, if you should be truthful."
Tafsir of Al-Qasas 28:49
Tafsir
Al-Kashshaf
Verse range: 28:49
Al-Qaṣaṣ: (49) "Say, 'Then bring a scripture...'"
{...is more rightly guiding than both of them} Meaning: more rightly guiding than that which was revealed to Moses (peace be upon him) and that which was revealed to me.
This conditional statement is of the type I mentioned previously: it is a condition used by one who is confident in a matter that is verified and true. This is because the impossibility of them bringing a scripture more rightly guiding than the two scriptures is a known, verified fact in which there is no room for doubt.
It is also possible that the particle of doubt (the conditional "if") is intended to mock them.
{But if they do not respond to you, then know that they only follow their [own] desires. And who is more astray than one who follows his desire without guidance from Allah? Indeed, Allah does not guide the wrongdoing people.}