Saʿīd b. Abī ʿArūbah – Allāh have mercy on him – said:

Whoever has not heard the differences of opinion, then do not consider him a scholar.

Ibn ʿAbd Al-Barr, Jāmiʿ Bayān Al-ʿIlm wa Faḍlihī no. 1521.

It is reported that Sufyān b. ʿUyainah – Allāh have mercy on him – said:

The most audacious people in giving verdicts (fatwā) are those who know the least about the differences of opinion amongst the scholars.

Op. cit. 1527.

It is reported that Imām Mālik – Allāh have mercy on him – was asked:

“Which kind of person is allowed to give verdicts (fatwā)?” He replied, “It is not allowed to give verdicts except for the person who knows what people have differed over.” He was asked, “Do you mean the differences of the people of (mere) opinions?” He replied, “No, the different opinions of the Companions of Muḥammad ﷺ, and the one who also knows the abrogating from the abrogated [texts] in the Qurān and in the ḥadīth of the Messenger of Allāh ﷺ – such a person can give fatwā.”

Op. cit. 1529.

It is reported that Yaḥyā b. Sallām – Allāh have mercy on him – said:

It is not right for the one who does not know differences of opinion to give verdicts, and it is not allowed for the one who does not know about the various statements [of the scholars] to say: I prefer such-and-such opinion.

Op. cit. 1534.