or anything else, citing the Quran and Sunnah as evidence in these matters will not benefit him unless the invalidity of that opposing argument is also demonstrated.

The invalidity of that opposing argument may be established both in general terms and in detail.

In general terms, anyone who has complete faith in Allah and His Messenger and knows with certainty what the Messenger intended will be certain that what he reported is true. He will know that any arguments opposing it are invalid, akin to the specious arguments of the sophists. As Allah Most High says:

“And those who argue concerning Allah after His call has been answered—their argument is invalid before their Lord. Wrath is upon them, and a severe punishment awaits them.”
Al-Shūrā: 16.

In detail, this is established by knowing why the opposing argument is invalid. This principle is the opposite of the principle advanced by a group of heretics, as al-Rāzī stated at the beginning of his book Nihāyat al-ʿUqūl (The Ultimate Reach of Reason). He maintained that transmitted revelation cannot under any circumstances be used as evidence in questions of religious fundamentals, because reasoning from it depends on uncertain premises and on ruling out any opposing rational argument. He further maintained that knowing that no opposing argument exists is impossible, since there may in fact be a rational proof that contradicts what the Quran indicates but has never occurred to the listener.