Bukhari

Hadith Commentary:
If it is a voluntary (nafl) fast, then it is better to break it and participate in such invitations, because this increases mutual love and creates social harmony.

Hadith Commentary:
(1)
One should attend a wedding feast (walimah); however, it is not necessary to eat the food there. Thus, it is mentioned in the hadith that the Messenger of Allah sallallahu alayhi wa sallam said:
“When you are invited to a meal, accept the invitation; upon arriving, if you wish, eat, and if you wish, leave it.”
(Sahih Muslim, Kitab al-Nikah, Hadith: 3518 (1430))

(2)
If someone is observing a voluntary (nafl) fast, it is permissible to break it for the sake of accepting an invitation, because this increases love and fosters mutual relations.
Hafiz Ibn Hajar rahimahullah has transmitted a narration from al-Tabarani that a man arranged a meal and someone said:
“I am fasting.”
The Messenger of Allah sallallahu alayhi wa sallam said:
“Your brother has invited you and has made an effort in this regard; break your fast, and if you wish, fast another day in its place.”
(al-Mu‘jam al-Kabir by al-Tabarani: 152/4, no. 3264, Maktabat al-Ma‘arif edition)
However, its chain of narration is weak, but it can be presented as corroboration and supporting evidence.
(Fath al-Bari: 308/9)

Hadith Commentary: Benefits and Issues: In this blessed verse, the word "Salat al-Asr" (afternoon prayer) was mentioned as an explanation (tafsir). That is why she (Aisha radi Allahu anha) had it written in her personal codex (mushaf), and the Noble Prophet (sallallahu alayhi wa sallam) informed the noble Companions (radi Allahu anhum ajma'in) of it at the time of teaching. Therefore, when the Imam's codex (mushaf) was written, according to which other codices were prepared, this word was not written. As for the issue that the hadith is khabar wahid (solitary report) and the Qur'an is established by tawatur (mass transmission), the answer is that the same hadith which informs us of its being Qur'an also establishes its abrogation. Now, since it is no longer Qur'an, the condition of tawatur does not apply to it. The condition of tawatur is only for that verse which is present in the Qur'an. Therefore, those who considered it Qur'an also considered this explanation (tafsir) to be abrogated, and those who did not consider it Qur'an but rather an explanation, wrote it in their personal codices for their own remembrance or supplication. In any case, from all the aforementioned ahadith, it is established that the meaning of "Salat al-Wusta" (the middle prayer) is the Asr prayer. Therefore, this is the correct and preferred opinion, and other opinions are not correct. However, since there are five prayers, each prayer can be considered as being in the middle and thus called the middle prayer, and this has indeed been done. Even to the extent that, by considering the conjunction ('atf) to indicate distinction, even Jumu'ah (Friday prayer), apart from the five prayers, has been called the middle prayer, and some reason has been stated for each opinion.