Is it required for the chain of narration to match when we say "on the condition of al-Bukhari and Muslim" or "on the condition of one of them"?

The questioner : Is it required, when we say "on the condition of one of them" or "on the condition of both," for the chain of the sanad to match, or ...?

The Shaykh : Some of them say this, but I do not see that as necessary unless there is something in the context that necessitates noting this point. For example: Sufyan ibn Husayn, or rather Husayn ibn Sufyan, who narrates from al-Zuhri? Sufyan ibn Husayn is among the men ofThe Shaykh : ...reliability, and he is truly trustworthy. However, the scholars, may Allah reward them with good, in their trust in their scrutiny of the narrations of the trustworthy, let alone those of others, said: Sufyan ibn Husayn is trustworthy from all his sheikhs except from al-Zuhri. He is an imam among the imams of the Muslims. If Sufyan ibn Husayn narrates from any trustworthy narrator, even if that narrator's reliability is less than the reliability of the Imam al-Zuhri, his narration is a proof. But if Sufyan narrates from al-Zuhri himself, his hadith remains weak. Why? Note, as I recall, it may be him or someone else, so let us remember. Note that his narration from al-Zuhri was recorded in his notebooks, and then these notebooks were lost, so he began narrating without verifying his memorized texts... and thus additions and omissions appeared in them. They said he is a proof except in his narration from al-Zuhri. So if there is such a specific warning in the narration, and this is the principle that not ... .