Knowing the evidence in issues has several benefits.

The Shaykh : I say, may Allah reward you, it is befitting for the mufti to read the evidence for the request of the one seeking a ruling, if his intention is not to be stubborn and to challenge, because this indicates awareness from the one seeking a ruling and that he wants to build his worship on insight and on evidence from the Shari'ah of Allah (Mighty and Majestic). Because knowing the evidence has benefits, among which is a person's conviction in the ruling, is that not so? And among them is also that the ruling becomes an argument for him against others, meaning that even if he says, "This is forbidden," and another opponent says, "It is not forbidden," he can convince him with the evidence. And among them is that it becomes an argument against him as well, because he cannot contradict the implication of the evidence, unlike if he merely sees that this is forbidden and this is forbidden, he might contradict.