When is it permissible for a mujtahid to issue a ruling on a hadith, classifying it as an authentic hadith or a weak hadith?

The questioner : Regarding the Prophetic hadith, when is it sufficient for the one who publishes the hadith, or when is it sufficient for the one who wishes to publish the hadith to rely on its chains of narration, such that he says: "This is weak," and is content with that, without investigating the remaining sources to see if there are other chains or not?

The Shaykh : If he intends to base a legal ruling on the hadith, and he stops at its weak chain, then builds the legal ruling upon it without exhausting his effort to trace whether it has other chains or corroborating narrations, this is not permissible. However, if it is merely to clarify the state of this chain of narration before him, and it appears to him that it is weak, and he has not weakened the hadith itself but only the chain of narration, then there is no harm in that. For this reason, the scholars of hadith stated in the terminology: it is not permissible for one who stops at a hadith with a weak chain of narration to say "the hadith is weak," but rather he should say "its chain of narration is weak," due to the possibility that there may be something that strengthens it. But if a man is knowledgeable about hadith and the chains of hadith, and he exhausts his effort, and traces its chains, and finds nothing in them that strengthens the hadith, despite the possibility that there may be something he missed, in this case, if he says "the hadith is weak," it is permissible, meaning after exhausting the effort in tracing the chains of the hadith. As for the first case, it is not permissible for him to say anything other than "its chain of narration is weak."

The questioner : May Allah reward you with good.