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

The Shaykh : A questioner here asked a question that contains some strangeness. After saying "In the name of Allah, the Most Merciful, the Bestower of Mercy," he asked: What are the reasons for the differences in the rulings of hadith scholars regarding the grading of a hadith as authentic, weak, fabricated, etc.?
One of us reads the same hadith from more than one hadith scholar; one makes it authentic, another makes it weak, a third makes it fabricated, a fourth makes it invalid, and a fifth makes it denounced. There are many and numerous examples, and those who have studied something of this science know them. This is the claim of the questioner. He said, "And this is what has caused students of knowledge and Muslim youth to shy away from studying hadith and resort to taqlid and taking from a shaykh. We ask that you mention the aforementioned reasons with something—so be it, it is on his responsibility—with some clarification of the matters of hadith science."
We say, in answer to this question, that the questioner has exaggerated greatly 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 is one hadith... what are the 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 do not know what else he mentioned."

The questioner : ... .

The Shaykh : ...invalid, etc.
This is a fictional depiction of reality. But as I told you just now, that does not mean that hadith scholars do not differ. This is what should be explained and mentioned: the reason or reasons that necessitate such a difference.
...that hadith science is like any science based on research, ijtihad (independent legal reasoning), and study, and every mujtahid (a scholar qualified to derive rulings) has a share. In this state, what is the reason for the difference of the imams who perform ijtihad in legal rulings? These disagreements have many reasons, but among them, what is appropriate to mention now are two fundamental, essential reasons. 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 is only asked about the ruling contained in the hadith, and he issues a fatwa (a scholarly legal ruling) and hits the mark... the other who did not look at the hadith has to exert ijtihad and gets the ruling wrong because he did not look at the hadith. Another reason is that both may have looked at the hadith, but this one understood it in one way and that one understood it in another way. In saying that this difference in understanding often returns to the first reason, it may be good to give an example of that.
The famous hadith in al-Bukhari and Muslim and others And a written question came to us with many questions, among which was: How do the Hanafis interpret the hadith as "no complete prayer" while others say "no valid prayer"? What is the reason? So I say now that the hadith is authentic according to everyone. It 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," while the Shafi'is and others understood it as "no valid prayer." What is the reason for the disagreement? It also returns to another text in which they differed in understanding. Such a difference should not occur in that other text because it is the Qur'an, and it is the saying of 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 aforementioned hadith.
The verse does not mean what appears from what comes to mind from this phrase alone. Rather, its meaning is surprising to one who has no knowledge, naturally, and that meaning is meaning: Pray what is easy for you of the night prayer. How did we derive this meaning? From the context of the verses. All the verses speak about standing in night prayer. Amen, will he mention it?

The questioner : ... .

The Shaykh : meaning: Standing for Allah meaning: Pray what is easy for you of the night prayer. It is established by the Qur'an that the obligatory in the recitation in prayer is absolute recitation, because He said And based on that, they say: Since the Qur'an restricted it, it is not permissible to specify it with a hadith of a single narrator (ahad), because, as they claim, it conveys only probability, 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 those with certain establishment and those with probable 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. First, a Qur'anic text was understood incorrectly on the surface of the text, separated from the context and what precedes it. Second, they said this is Qur'an, and it is not permissible to specify it with an ahad hadith even though the Imam of Imams, truly, in hadith, namely al-Bukhari, refuted them. He stated explicitly in his private treatise on recitation behind the imam by saying: "The report has reached us in a mass-transmitted manner (mutawatir) from the Messenger of Allah (peace and blessings be upon him)." This is the Imam of hadith scholars ruling on a 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 absolutely no relation to this research, and the hadith is mutawatir, not an ahad hadith. Nevertheless, the one who erred in the previous understanding then followed on its surface, and this is a verse that cannot be specified by a hadith. So what do they do with the hadith? They suspend the hadith absolutely because it is an ahad hadith. They say: We do not act upon it and make it effective in a ruling that does not conflict with the verse. So we say the obligation of reciting al-Fatihah, not its being a pillar, because if we said reciting al-Fatihah is a pillar, we would contradict the verse, as they claim. But if we say reciting al-Fatihah is obligatory, 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, so we say its meaning is "no complete prayer." This is one of the reasons for the difference in fiqh (Islamic jurisprudence). It returns to two basic reasons: not looking at the report, or looking at the report but differing in understanding. Such a thing 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 authentication, and the one who weakened it erred. Why did this one hit the mark and why did that one err? In many cases, the one who weakened the hadith is correct in weakening it, but it is a relative correctness. That is, the 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.