Bukhari

Hadith Commentary:
The relevance of the chapter is derived from the fact that the Prophet (sallallahu alayhi wa sallam) ordered a single individual to carry out the punishment.
He implemented the legal ruling, that is, the stoning (rajm).
Some have said that the Prophet (sallallahu alayhi wa sallam) accepted the statement of each party, even though each was alone, and affirmed it.
Imam Ibn Qayyim (rahimahullah) has stated: The solitary report (khabar wahid) is of three types: first, that which is in accordance with the Qur’an; second, that which provides detail to what is in the Qur’an; third, that which contains a new ruling not found in the Qur’an.
In any case, it is obligatory to follow it, because Allah the Exalted has given a distinct command to obey the Messenger of Allah (sallallahu alayhi wa sallam) in addition to His own obedience.
Thus, if only that solitary report is acceptable which is in accordance with the Qur’an, then the obedience to the Messenger would not be separate and specific. And as for the Hanafis, who say that an addition to the Qur’an cannot be established by a solitary report, but rather it is necessary for the report to be well-known (mashhur) or mass-transmitted (mutawatir),
they themselves have acted contrary to this principle in many issues, such as the permissibility of ablution (wudu) with nabidh tamr (date infusion), the threshold for theft (nisab sariqah), the dowry (mahr) not being less than ten dirhams, the prohibition of combining a woman and her paternal or maternal aunt in marriage, pre-emption (shuf‘ah), mortgage (rahn), and hundreds of other issues in which ahadith have been narrated, and despite this, the Hanafis have made additions to the Book of Allah based on them.
I say: No principle of the Hanafis is consistent.
In their principles, they write that the solitary report and the statement of a Companion (radi Allahu anhu) are also proof, by which analogy (qiyas) is abandoned, yet in hundreds of issues they act upon analogy against the hadith.
In their principles, they write that for an addition to the Book of Allah, a well-known or mass-transmitted report is necessary, yet in issues they make additions based on solitary reports, and wherever they wish, they abandon even the well-known report on the pretext that it is contrary to the Book of Allah.
For example, the ahadith regarding oath with a single witness (yamin ma‘a al-shahid al-wahid).
In short, these are such strange principles that are not understandable, and the truth is that these are not the principles of Imam Abu Hanifah (rahimahullah); rather, the later ones have established them, and they alone will be answerable before Allah the Exalted. May Allah grant justice.

Hadith Commentary:
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The relevance of this hadith to the chapter heading is established in several respects.
The first point is that two parties appeared before the Messenger of Allah (sallallahu alayhi wa sallam), and each party consisted of a single person.
The Prophet (sallallahu alayhi wa sallam) listened to their statements, affirmed them, and issued a ruling regarding each one.
The second application is that the Prophet (sallallahu alayhi wa sallam) sent a man from the tribe of Aslam, Anas (radi Allahu anhu), to the woman in order to inform her of the situation.
She listened to the words of the Messenger of Allah’s (sallallahu alayhi wa sallam) envoy and confessed her crime.
Then, a single man carried out the prescribed punishment of stoning (rajm) upon her.

➋
In any case, from this hadith as well, the authority of a solitary report (khabar wahid) is as clear as daylight. Furthermore, in this hadith, the Sunnah of the Messenger of Allah (sallallahu alayhi wa sallam) has been referred to as the Book of Allah, because in matters of the Shari‘ah, the Messenger of Allah (sallallahu alayhi wa sallam) did not speak except by revelation.