Bukhari

Hadith Commentary:

That is, he came as an uninvited guest (ṭufaylī), and the name of this person is not known. The Messenger of Allah (sallallahu alayhi wa sallam) sought permission from the host so that his heart would be pleased, whereas in the invitation of Abu Talhah (radi Allahu anhu), he did not seek such permission because Abu Talhah had not specified the number of guests, while this person had fixed the number at five. Therefore, the Prophet (sallallahu alayhi wa sallam) considered it necessary to seek permission.

In the hadith, there is mention of a butcher and those who sell meat. From this, the permissibility of this profession is established.

Hadith Commentary:
(1) (al-Hakkam) refers to the one who sells meat, and (Jazzar) refers to the one who slaughters camels, while Qassab is used for one who slaughters goats and the like. When the ruling of permissibility or dislike is established for one category, then due to the generality of the underlying reason, it will also be established for the remaining categories.

(2)
In the hadith, the mention is of the Qassab, that there is no harm in adopting this profession. On this basis, adopting the profession of selling meat and slaughtering camels is also permissible. However, according to the scholarly approach of Imam Bukhari rahimahullah, the clarification of this hadith will be as follows: when the sale and purchase of mixed dates is permissible, then selling meat along with bones is also permissible.
You have made some progress from the previous heading, because raw and fine dates were of the same kind, whereas sinews and bones are not a type of meat. Despite this, selling sinews and bones along with meat is permissible.

(3)
It should be clear that an uninvited guest is called a Tufaili.
If the owner of the house grants him permission, he may join; otherwise, he must return.
And Allah knows best.

Hadith Commentary:
This hadith has already been mentioned above.
Imam Bukhari rahimahullah has also established the purpose of this chapter from this hadith: that attending an invitation and eating food without being invited is not permissible, but if the host grants permission, then it becomes permissible.
This hadith also sheds light on the compassion and mercy of the Noble Prophet sallallahu alayhi wa sallam, that he sallallahu alayhi wa sallam could not bear for anyone to remain hungry.
This is precisely the characteristic that a God-fearing, noble person should possess.
Sallallahu alayhi wa sallam.

Hadith Commentary:
(1)
From this hadith, the etiquettes of invitation are understood: only those individuals whom the host has invited should participate in the invitation; joining without an invitation is an unreasonable act.
If someone does so, the guest must inform the host; however, courtesy and good manners require that the host should not humiliate such a person, but rather grant permission for him to join the invitation.

(2)
Imam Bukhari rahimahullah has established the heading based on the host’s permission, indicating that this is his right, and participation in the meal is dependent upon his permission. If he grants permission, it is permissible; otherwise, participating in the invitation is an infringement of his right, regarding which there may be questioning in this world and the Hereafter.

Hadith Commentary:
However, it is not permissible to go to anyone’s house in this manner, nor to take someone along with oneself, unless it is a sincere friend—then that is a different matter.

Hadith Commentary:
Insisting on taking another person along when invited depends on the circumstances and context.
It is not permissible to take someone else to everyone’s house.
If it is a sincere friend, that is a different matter; however, regarding this, one should mention it at the time of receiving the invitation, just as the Messenger of Allah (sallallahu alayhi wa sallam) said regarding Aisha (radi Allahu anha):
“She will also be with me.”
If the matter has not been settled beforehand, then it is subject to the discretion of the household, as is indicated in this hadith.
If they wish, they may grant permission, and if they do not grant permission, then the person should be sent back.
In any case, one must certainly consider the appropriateness of the situation.
It is not permissible to do so unconditionally.
And Allah knows best.

Hadith Commentary:
The relevance to the chapter is derived from the fact that he had food prepared specifically for five people, so certainly there must have been some form of formality (takalluf) involved.
It is understood from this that the host has the authority to permit or not permit someone who comes without an invitation.
Attending an invitation without being invited is prohibited, except when it is certain that the host will be pleased by his coming and there is mutual informality between them; in that case, it is permissible.
Similarly, if it is a general invitation, then attending it is also permissible.

Hadith Commentary:
(1)
The noble Companion named Abu Shu‘aib made considerable effort (takalluf) in preparing a meal for the Messenger of Allah (sallallahu alayhi wa sallam); he had the meat specially prepared by an expert and presented it to the Prophet (sallallahu alayhi wa sallam).
Some individuals have stated that inviting a sixth person to the meal constitutes undue effort (takalluf).

(2)
In any case, making special arrangements (takalluf) on the occasion of hosting guests and brothers is permissible and allowed.
Arranging for meat for them is a commendable trait.
It is said that meat is the chief of all foods in this world and the Hereafter.
And Allah knows best.

Explanation:
1:
From this it is understood that joining an invitation as an uninvited guest, acting as a hanger-on without an invitation, is an unethical act. However, if permission is obtained from the host, then there is allowance for it.