Shaykh al-Islām Ibn Taymiyyah (d. 728 AH) said: A scholar may have a legitimate reason for choosing to act/not act [in a fiqh issue] due to a plethora of aḥadīth that he possesses, although we may not know the [specific] reasons. For truly, the ways that knowledge itself is propagated and attained are vast. Furthermore, we are not acquainted with what each individual scholar may hold in their innermost thoughts. A scholar may clarify his evidence [in support of his opinion], or he may not. Even if he discloses it, this [evidence] may or may not reach us. And even if it reaches us, we may or may not fully comprehend how his opinions were interpreted [based on the original evidence], assuming the evidence itself is appropriate [for the issue at hand].
 

Considering this, it is impermissible for us to leave an opinion that is supported by an authentic ḥadīth and espoused by a group of scholars [in any fiqh issue] for another opinion taken by a more knowledgeable scholar who may also have evidence.

For verily, mistakes plague the opinions of scholars far more than they could ever plague the Islamic legislation itself. Truly, this sharī’ah is the evidence of Allāh Himself against all His servants, whereas the opinion of a scholar does not hold such a lofty position.

Source: Majmūʿ al-Fatāwá 10:302-303
Translated by: Riyāḍ al-Kanadī