What are the reasons for the variation in the rulings of hadith scholars regarding the grading of a hadith as authentic, weak, or fabricated?

The Shaykh : A questioner here asked a question that contains some oddity. He said: After the Basmala: What are the reasons for the variation in the rulings of hadith scholars in explaining the grade of a hadith as authentic, weak, false, or fabricated, and so on? One of us reads the same hadith with more than one hadith scholar; one grades it as authentic, another as weak, a third as fabricated, a fourth as invalid, and a fifth as denounced. There are many numerous examples, and those who have studied something of this science know them. And this, according to the claim of the questioner, is what causes students of knowledge and Muslim youth to shy away from studying hadith and resort to taqlid (following a scholar without knowing his evidence) and taking from a shaykh. We ask you to mention the aforementioned reasons, along with a little—well, it is up to you!—along with some clarification of matters of hadith science.
We say in answering this question: The questioner has greatly exaggerated in depicting the disagreement existing among hadith scholars. I say this while acknowledging that we cannot deny the existence of disagreement, but it is not to the extent that the questioner depicts it; that one hadith has five, six, what? contradictory rulings. I think if this questioner were truly a student of knowledge, we would have said to him, even in a private session: Give us one example of a hadith where one hadith scholar says it is authentic, another says it is weak, a third says it is fabricated, a fourth says it is denounced, and I don't know what else he mentioned, invalid, and so on. This is a fictional depiction of reality. But as I said earlier, that does not mean that hadith scholars do not differ. This is what should be explained, and the reason or reasons that necessitate such a difference should be mentioned.
I want to remind you that hadith science is like any science based on research, ijtihad (independent legal reasoning), and study, and in this state, every mujtahid (a scholar qualified to derive rulings) has a share. So what is the reason for the difference of the imams who perform ijtihad in the rulings of the Shari'ah (Islamic sacred law)?
There are reasons. These differences have many reasons, but among them, two fundamental, basic reasons are suitable to mention. The first is that one person looks at a hadith and the other does not look at it. So the one who looked at the hadith, when asked about the ruling contained in the hadith, issues a fatwa (a scholarly legal ruling) and hits the mark. The other one who did not look at the hadith performs ijtihad and errs in the ruling because he did not look at the hadith.
Another reason: It may be that both looked at the hadith, but this one understood it in one way and this one understood it in another way. I say that this difference in understanding often goes back to the first reason. And it is perhaps good to give an example of that. The famous hadith in "al-Bukhari" and "Muslim" and others: , and a written question came to us among many questions, including that the group interprets the hadith as: "No complete prayer," and people say: "No valid prayer." What is the reason? So I say now: The hadith is authentic with everyone. is a suitable example for the second reason, which is the difference in understanding. Why did they differ in the ruling? Because the Hanafis understood it as: "No complete prayer," and the Shafi'is and others: "No valid prayer." What is the reason for the disagreement? It also goes back to another text in which they differed in understanding, and it is not appropriate to mention this disagreement in this other text because it is the Qur'an, and it is His saying, the Exalted: . When some of them erred in understanding this verse, they were compelled, as a result of this error, to fall into another error, which is the error in understanding the previous hadith. The verse: does not mean what appears from what comes to mind from this phrase alone, but its meaning is strange to one who has no knowledge, of course, and it is the meaning: ; that is: Pray what is easy for you of the night prayer. How did we obtain this meaning? From the context of the verses; all the verses speak about standing in night prayer.
Who remembers?

The questioner : .

The Shaykh means standing in the night, ; that is: Pray what is easy for you of the night prayer.
This is what all the mufassirun (exegetes) agreed upon, with no disagreement between them at all, neither Hanafi nor Shafi'i. But it is very unfortunate, and this is one of the effects of madhhab (school of jurisprudence) fanaticism and rigid taqlid (following a scholar without knowing his evidence), that this verse in the books of tafsir (Qur'anic exegesis) has the meaning you heard: ; that is: Pray. But when the one who specializes in the Hanafi madhhab comes, as if he forgets what the exegetes agreed upon regarding the meaning of this verse, he says: It is established by the Qur'an that the obligatory recitation in prayer is absolute recitation; because Allah said: . And based on that, they say: And since the Qur'an is certain in its establishment, it is not permissible to specify it with a hadith of a single narrator (ahad); because, as they claim, it conveys probability (zann), so it is not permissible in their opinion to apply the probable to the certain.
I said this in the printed treatise on the issue of ahad hadiths and in my lessons: This is a foreign philosophy in Islam; dividing hadiths into certain in establishment and probable in establishment, and arranging the difference in rulings between what is probable in establishment and what is certain in establishment. This is a foreign matter in Islam, and one of its effects is this issue we are discussing: is a Qur'anic text, first, that was misunderstood on the surface of the text, separated from the context and the preceding text. Second, they said: This is the Qur'an, it is not permissible to specify it with an ahad hadith: ; even though the Imam of Imams, truly, refuted them in the hadith, namely al-Bukhari. He explicitly stated in his special treatise on recitation behind the imam: "The report has become mutawatir (a mass-transmitted report) from the Messenger of Allah (peace and blessings be upon him)." This is the Imam of hadith scholars judging the hadith as mutawatir. So if the distinction between mutawatir hadith and ahad hadith in rulings were valid, the argument would be established regarding this hadith that it is suitable to specify the verse because it is a mutawatir hadith. But look, the verse has no relation to this research at all, and the hadith is mutawatir, not an ahad hadith. Nevertheless, the one who erred in understanding previously was then followed (taqlid) on its surface, and this verse is not permissible to be specified by the hadith. So what do we do with the hadith? Do we nullify the hadith absolutely because the hadith is ahad? He said: No, we implement it and rule with it with a ruling that does not contradict the verse. So we say by the obligation of reciting al-Fatihah (Surat al-Fatihah), not by its being a pillar (rukun); because if we said by the pillarhood of reciting al-Fatihah, we would collide with the verse in their claim. But if we say by the obligation of reciting al-Fatihah, by that we do not strike the verse and we take the verse on its surface as they understood it, and we take the hadith and say: Its meaning is: No complete prayer.
So this is one of the reasons for the difference in fiqh (Islamic jurisprudence). That goes back to two basic reasons: not looking at the report, or looking at the report but differing in understanding.
Something like this happened to the hadith scholars themselves. For example, a hadith that so-and-so authenticated and so-and-so weakened. The one who authenticated it, let us assume, hit the mark in the authentication, and the one who weakened it erred. Why did this one hit the mark? And why did this one err? In many cases, the one who weakened the hadith is correct where he weakened it, but it is a relative correctness; that is: This hadith that so-and-so authenticated, the one who weakened it looked at it from a path in which there is a weak man, and he did not look at the path that the first one looked at, which is a correct path. If the second one had looked at it, he would have met the first one and they would have agreed on the authenticity of the hadith. And this is very common. And sometimes the path is one, sometimes the path is one; so this one authenticates it and this one weakens it. This happens, indeed, it happens with the same person.