Bukhari

Hadith Commentary:
The statement of Sa’ib bin Yazid pertains only to his own companionship; otherwise, in the books of hadith, there are indeed many narrations transmitted from those noble companions as well.
It is certain that all the noble Companions exercised utmost caution in narrating hadith from the Messenger of Allah (sallallahu alayhi wa sallam).
This was out of fear that they might, by committing a misstatement, become among the living inhabitants of Hell, because the Prophet (sallallahu alayhi wa sallam) said: Whoever attributes to me a hadith which I did not say, let him take his seat in the Fire.
Therefore, the inference drawn by the deniers of hadith from this is invalid.
The narration mentions the Battle of Uhud.
This is the reason for its relevance to the chapter.
After the Noble Qur’an, it is obligatory upon every Muslim to accept the authentic, elevated, and reliable hadith. Whoever denies an authentic hadith is, in fact, denying the Qur’an itself, and this is not the way of any Muslim.

Hadith Commentary:
➊ In the first hadith, "some days" refers to the Battle of Uhud. Among the Muhajirun, the eminent companions would always accompany the Messenger of Allah (sallallahu alayhi wa sallam) in the battles, but in the Battle of Uhud, the fighting became so intense that, apart from Talhah (radi Allahu anhu) and Sa'd (radi Allahu anhu), no other Muhajir remained with him. According to the previous hadith, Miqdad (radi Allahu anhu) was present with the Messenger of Allah (sallallahu alayhi wa sallam) in such difficult circumstances, but he arrived after the most severe moments had passed. The specification of these two individuals in the hadith is with respect to the Muhajirun, because in Sahih Muslim it is mentioned that during the Battle of Uhud, the Messenger of Allah (sallallahu alayhi wa sallam) once faced such circumstances that there were seven Ansar and two Qurayshis with him. (Sahih Muslim, al-Fada'il, Hadith: 4641. (1789)) The two Qurayshi individuals refer to Talhah (radi Allahu anhu) and Sa'd (radi Allahu anhu); among the Muhajirun, only Talhah and Sa'd were with him.

➋ According to the second hadith, the reason these individuals did not narrate hadith was that they feared error and forgetfulness, lest they make a mistake. For this reason, they exercised caution in narrating hadith. Furthermore, the aforementioned statement pertains only to the companionship of Sa'ib ibn Yazid (radi Allahu anhu); otherwise, in the books of hadith, many narrations are also reported from these individuals. However, they certainly exercised caution.

And Allah knows best.