Answered by Shaykh Amjad Rasheed
When is it recommended to avoid the differences of opinion of other schools? What if something is recommended in our school and prohibited in another?
In our madhhab, it is recommended to avoid the differences of opinion of other schools, with three conditions:
First Condition:
Avoiding the difference of opinion should not make us fall into another difference of opinion.
The great scholars (imams) of our school used the example of separating the rakat of witr prayer from what preceded it: this is better in our school than to pray both together [i.e. making it 3 rakats, for example, with one set of salams]. The scholars of our school did not take into account the difference of opinion of Imam Abu Hanifa (Allah have mercy on him) who did not permit separating these rakats, because there are other great scholars who did not permit praying them together. Thus, if we were to avoid the difference of opinion of Abu Hanifa, we would fall into the difference of opinion of others.
Second Condition:
The opinion whose difference we are trying to avoid not go against an established sunna of the Prophet (Allah bless him and give him peace), or even a weakly-established sunna that can be acted upon in virtuous deeds (fada’il al-a`mal).
Thus, it is recommended to raise hands in prayer in known places, and the difference of those who said the prayer is invalidated by this was not taken to account, because this opinion goes against the authentically-established sunna.
Third Condition:
The difference of opinion should have some strength of proof.
Thus, the differences of the Literalists (Zahiriyya) are not considered of consequence, as Imam Nawawi chose, following Imam al-Haramayn who said: “The scholars of verification (muhaqqiqin) do not give any weight to the Literalists.” This was also chosen by Shaykh Ibn Hajar [al-Haytami].
And Allah alone gives success.