What is the ruling on learning one school of jurisprudence to act according to it, and is it permissible for one who has learned it to issue fatwas based on it when asked?

The Shaykh : We need a person to watch the sun for us when it sets, so that we break our fast according to the Sunnah, not according to your adhan.

The questioner : Good news.

Another questioner : O Shaykh, may Allah protect you, today...
Abu Layla : Please, O Shaykh, Ali.
Al-Halabi : In the name of Allah, and may the prayers and peace be upon the Messenger of Allah. As for what follows, a questioner asks: A Muslim has memorized one of the four schools of jurisprudence and acts according to its default rulings and dispensations. Is it permissible for him to issue fatwas to questioners based on it?

The Shaykh : It is not permissible for him to issue fatwas based on what he has learned from his school, except by stating that it is the position of so-and-so, and not on the basis that it is the knowledge he arrived at through his personal study. This is because the one who follows a scholar without knowing his evidence is not a scholar; the one who follows a scholar without knowing his evidence is merely a reciter who repeats what he has heard. Therefore, he must say, "The answer to what you asked, according to the school I have studied, is such-and-such," and he must not say, "The answer is such-and-such." The difference between the two answers is that the second answer, which asserts with certainty that it is such-and-such, is the domain of the scholar who knows the Book and the Sunnah. As for the one who follows a scholar without knowing his evidence, even if he is considered one of the great scholars, as long as he is one who follows a scholar without knowing his evidence, he is not a scholar. In the view of the scholars, the scholar is, as Ibn al-Qayyim (may Allah have mercy on him) said:
"Knowledge is: Allah said, His Messenger said, The Companions said; it is not obfuscation," and so on. This is the scholar. As for the one who spends his life studying the opinions of a specific school without knowing whether its evidence is from the Book, the Sunnah, scholarly consensus, or analogical reasoning, that is the one who follows a scholar without knowing his evidence. By the consensus of the scholars, the one who follows a scholar without knowing his evidence is called ignorant, not a scholar. Therefore, it is stated in the books of Islamic jurisprudence, in the book on judgment, that an ignorant person must not be appointed as a judge. The commentator said, meaning the one who follows a scholar without knowing his evidence: no matter how knowledgeable he is in his school, he is one who follows a scholar without knowing his evidence, and not the scholar who is permitted to issue fatwas. And one of the fruits of the distinction between the true scholar and the scholar whom some of these followers of scholars have aptly named the "figurative scholar," meaning the one who follows a scholar without knowing his evidence, is that the true scholar issues fatwas based on evidence, saying, "Allah said," or "The Messenger of Allah said," or "There is scholarly consensus on this," or "There is no explicit text, but this is my independent legal reasoning and my opinion; if anyone has something better, let them bring it to us." As for the figurative scholar, meaning the one who follows a scholar without knowing his evidence, he says, "Based on my school." Since the general public do not distinguish between true knowledge and the figurative scholar, this figurative scholar must say, "My school says such-and-such," and not say, "The answer is such-and-such," because he does not know or understand. Yes.