1- First and foremost, one must have a firm belief in all that is related in both the Quran and the Sunnah. The Word of Allah and the authentic statements of the Messenger of Allah are the foundational sources of the entire religion. Thus, an unshakable, unwavering belief in these two authentic sources is imperative for any proof related to Aqeedah.
2- Secondly, a firm certainty that every issue related to Islamic belief criteria is covered in the Quran and the Sunnah. Be it addressed directly, or eluded to, every issue regarding the proper belief system is covered within the two key source texts of the Islamic religion. Sometimes, it is addressed thoroughly in both, while other times it is addressed, or mentioned, in the Quran, and then further expounded upon in the Sunnah. but rest assure, the Quran and the Sunnah has covered every issue regarding core beliefs.
3- Thirdly, there is absolutely no abrogation with regards to Aqeedah and historical accounts. Once a narration related to Aqeedah is deemed authentic, and accurately traced back to the Prophet through an authenticated source of transmission, then there is no abrogation, or naskh, regarding points of Aqeedah. Fiqh, or religious understanding may be abrogated. Rulings and judgements may have been adjusted or abrogated during the Prophet’s lifetime. But the authentic foundations of the Aqeedah, or core religious belief system, has never, and will never be subject to abrogation.
4- Fourthly, there is absolutely no contradiction between the Quran and the Sunnah. Some may assert claims of contradictions between narrations or accounts in the Sunnah, between the Quran and the Sunnah, or between verses within the Quran itself. Despite the claims, there is absolutely no contradictions in any of the aforementioned scenarios, and any seeming contradiction is in fact due to a lack of a thorough understanding of the source texts. The Quran in its entirety is the authentically preserved original text, with no contradiction, and the Islamic scholars are to be referred to for a clearer understanding.
The same stands true regarding the Sunnah. Once the chain and text of the narration has been authentically verified, there will be no contradiction found between it and another authentically verified hadith. Rather, both of them are correct.
Sometimes, there may seem to be an apparent contradiction, due to slight variations between one text wording or chain of transmitters, versus another. Maybe two narrations seem contradictory for other reasons. So, when faced with such seeming contradictions, then seek a more thorough understanding from the people of knowledge, ie. the wIslamic scholars, about this contradiction on how to understand it. They will surely guide and enlighten with regards to these apparently contradictory texts.
5- Fifth and lastly, there is no contradiction between authentic religious text and sound reasoning. The Quran and the Sunnah are in line with and revealed to cultivate sound mind and reasoning. Thus, it will never contradict sound logic. If there is any feeling the two are contradicting, then it is an indication of need for further study, further cultivation, or even a complete overhaul of what has been perceived as ethical or logical. Sometimes, an individual's environment, culture, or rearing could cause some distortions in their individual logic, but the Quran and the Sunnah will always affirm the Laws of Sound Reasoning and the Laws of Logic.
