Bukhari

Explanation:
In the narration of Isma‘ili, it is mentioned that Amir Mu‘awiyah radi Allahu anhu delivered a sermon to us. Hafiz Ibn Hajar states that perhaps Mu‘awiyah radi Allahu anhu forbade the two Sunnah (voluntary) units after ‘Asr. However, from the narration of ‘A’ishah radi Allahu anha, it is established that she used to perform them, but she did not perform them in the mosque. Most scholars have counted this among the special characteristics of the Prophet (sallallahu alayhi wa sallam), just as he used to observe the continuous fast (wisal) and forbade the ummah from it. Similarly, the ummah is not permitted to perform voluntary prayers (nafl) after ‘Asr.

Hadith Commentary:
(1)
Hazrat Amir Muawiyah radi Allahu anhu is negating the performance of two rak‘ahs after ‘Asr by the Messenger of Allah sallallahu alayhi wa sallam, whereas Hazrat A’ishah radi Allahu anha states that the Messenger of Allah sallallahu alayhi wa sallam never abandoned the two rak‘ahs after ‘Asr.
(Sahih al-Bukhari, Mawaqit al-Salat, Hadith: 591)
Since Hazrat A’ishah radi Allahu anha is affirming something, her statement will be given preference, because according to the principles of jurisprudence, affirmation of something takes precedence over its negation.
It is possible that Hazrat Muawiyah radi Allahu anhu was not aware of the performance of the two rak‘ahs after ‘Asr, because the Messenger of Allah sallallahu alayhi wa sallam used to perform them in his house.
As Hazrat A’ishah radi Allahu anha states, the Messenger of Allah sallallahu alayhi wa sallam did not perform them in the mosque.
(Sahih al-Bukhari, Mawaqit al-Salat, Hadith: 590)
It should be noted that the Messenger of Allah sallallahu alayhi wa sallam forbade performing any kind of prayer after ‘Asr.

(2)
This prohibitive ruling does not contradict the aforementioned action of the Prophet sallallahu alayhi wa sallam, because his prohibitive command pertains to non-causal (ghayr sababi) prayers, and his performance of two rak‘ahs was due to a specific cause: he was unable to perform the two rak‘ahs after Zuhr because of the arrival of the delegation of ‘Abd al-Qays, so he performed those rak‘ahs after ‘Asr. And it was his unique characteristic that whatever action he began once, he would then persist in it.
(Fath al-Bari: 2/82)

Hadith Commentary:
➊
These ahadith indicate the virtue of Muawiyah (radi Allahu anhu), that along with being distinguished by the honor of companionship (sahabiyyah), he was also a jurist (faqih), as is evident from the response of Ibn Abbas (radi Allahu anhu).
Those elders considered Amir Muawiyah a jurist and regarded his legal practice as authoritative.
Performing witr as a single rak‘ah is itself established from the Messenger of Allah (sallallahu alayhi wa sallam).
This was the practice of Muawiyah (radi Allahu anhu).
The claim of Allamah Ibn at-Teen that none of the jurists (fuqaha) held the view of witr being a single rak‘ah is a claim without evidence, as Hafiz Ibn Hajar (rahimahullah) has noted.
(Fath al-Bari: 7/132)

➋
There are numerous ahadith regarding Muawiyah (radi Allahu anhu) present in the books of hadith which indicate his virtue, but they were not in accordance with the conditions of Imam Bukhari (rahimahullah), hence they were not mentioned.
The Messenger of Allah (sallallahu alayhi wa sallam) summoned Muawiyah (radi Allahu anhu) for a certain task; it was found that he was eating. This happened two or three times, so the Prophet (sallallahu alayhi wa sallam) said:
“May Allah never fill his belly.”
(Sahih Muslim, al-Birr wa’s-Silah wa’l-Adab, Hadith: 6628(2604))
From this hadith, it is understood that it was a task which only Muawiyah (radi Allahu anhu) could perform; otherwise, the Messenger of Allah (sallallahu alayhi wa sallam) would have assigned it to someone else.
As for the words at the end of the hadith, they were not in the form of a curse (bad-du‘a), but rather an expression of affection.
In Sahih Muslim, this hadith is titled with these words:
(Bab: Whoever the Prophet (sallallahu alayhi wa sallam) cursed, reviled, or supplicated against, though he was not deserving of it, it would be a purification, reward, and mercy for him)
“Whoever the Messenger of Allah (sallallahu alayhi wa sallam) cursed, spoke ill of, or supplicated against, though he was not deserving of it, then those prophetic words would be a means of purification, reward, and mercy for that person.”
In any case, there is no reason for any change in the title by Imam Bukhari (rahimahullah), as some commentators have tried to suggest.
And Allah knows best.