The one who follows a scholar without knowing his evidence is not a scholar by consensus.

The Shaykh : And the one who follows a scholar without knowing his evidence is not a scholar by the consensus of the scholars. The one who says, "So-and-so the Shaykh said," or "So-and-so the Shaykh issued a ruling on such-and-such"; this is not of knowledge in any way. Rather, this is of the ignorance to which the Messenger of Allah (peace and blessings be upon him) referred in the authentic hadith. It is what the two Shaykhs narrated in their "Sahihayn" from the hadith of Abdullah ibn Amr ibn al-As (may Allah be pleased with them both). He said: The Messenger of Allah (peace and blessings be upon him) said: . This is an authentic hadith, and in it the Messenger (peace and blessings be upon him) explicitly stated that knowledge will disappear gradually. Knowledge does not depart by being plucked out, with our Lord plucking it from the people of knowledge and virtue. Rather, the people of knowledge die, which is the Sunnah of Allah in His creation. Then there remain people who do not know anything of knowledge.
And I return to remind you: knowledge is "Allah said" and "The Messenger of Allah said," not "So-and-so said" and "So-and-so issued a ruling." And this is our reality in the present age.
Therefore, we advise all our Muslim brothers, and especially those who are with us on this path and the straight path in following the Book of Allah and the hadith of the Messenger of Allah, to ask these muftis. I do not say that they should perform independent legal reasoning, for they are not qualified for independent legal reasoning. Rather, they should ask the muftis when they issue a ruling to them with their opinion on an issue: "Where did you get this from?" If it is from the language of the present age today, being precise in what concerns the gathering of wealth, and they draw attention to the fact that it is part of the Islamic system that rulers and governors who become wealthy and rich after taking up their positions should be asked: "Where did you get this money from?" Then it is even more fitting that regarding knowledge, they be asked: "Where did you get this by which you issue rulings to the people?" If they say, "Allah said," we say to them: "Explain to us the saying of Allah as the Salaf explained it, not as you see it and as others of the people of opinion in this age see it." And if they say to us, "The Messenger of Allah (peace and blessings be upon him) said," we ask them: "Is this hadith authentic or not authentic?" If they say, "This is an authentic hadith," then we hold them accountable for it, and it is not our responsibility. Because it is supposed that they are people of trust. If they issue a ruling to us with a weak hadith, and the reality is that it is a hadith, and they did not issue a ruling with a hadith whose reality was weak, but said that it is an authentic hadith; then they bear what they have been held accountable for. Because they are the ones responsible for delivering the trust to the people.