Answered by Shaykh Amjad Rasheed
Why has the Minhaj of Imam al-Nawawi been made the reference point for fatwa (formal legal opinion) and reliable positions in our madhhab?
It is well known that Imam al-Nawawi, may God have mercy upon him, is the pillar of our madhhab among the late scholars, so what he states and deems weightier in the madhhab is relied upon, not anything else. This is the position of the majority of our imams. Hence, all of his books are relied upon, but if they differ on a ruling, then his book Al-Tahqiq is given precedence. This is what has been stated in the books of the scholars, such as Shaykh Ibn Hajar in his Tuhfa (1.39). However, Ibn Hajar [h: goes on to say in his Tuhfa] about the foremost book of Imam Nawawi: [h: All that has been said in this regard] is an approximation. In reality, when these books differ, it is obligatory to refer to what the reliable late scholars have said [h: on the matter] and to follow what they have deemed strongest.
So from this, we can recognize the mistake of what some people repeat [h: when they say] that the Minhaj is always given precedence over other books. This doesnt mean that the Minhaj is not relied upon: it is relied-uponjust like his others books arebut it should not be put foremost without exception, as Shaykh Ibn Hajar pointed out.
However, the scholars of the late Shafii school may not be blamed for their dedicating themselves to the Minhaj; reading it, memorizing it and explaining it. The secret behind this is that it is a concise summary that comprises most investigations, questions, and essential rulings in a language that is succinct, easy and accurate; [h: everything is] excellently arranged and extremely refined; and it points out the differences of opinions in the madhhab without unnecessary elaboration. Note that his book al-Tahqiq is unfinished, so the [h: scholars] busied themselves [h: instead] with what gives complete benefit.