Is the brotherhood (mu'akhah) mentioned in the hadith of Salman and Abu Dharr (may Allah be pleased with them both) specific to that time, or is it general?

The questioner : A brother asks: We understood from the narration of Salman and Abu al-Darda' that when the Messenger of Allah (peace and blessings be upon him) established brotherhood between them, it was permissible for one of them to sit and talk with the other's wife in his absence, and similar matters. Can we know all the aspects of this... and what is permissible and what is not permissible, and what follows from this brotherhood? Is this brotherhood permissible and possible in all circumstances and conditions, or was it specific to the Messenger of Allah (peace and blessings be upon him)?

The Shaykh : There is no doubt among the scholars that the brotherhood (mu'akhah) mentioned in the hadith of Abu al-Darda' and Salman is a ruling that has passed and ended, and it does not return until the end of time. Therefore, the rulings that were attached to such brotherhood have also ceased and ended. Consequently, it is not permissible for a Muslim today to enter the house of his Muslim brother in Allah as long as the husband of the woman in the house is not present, or at least there is not in the house someone who is considered a mahram (a relative one may not marry) to the wife. It is not permissible to enter or to mix with her, based on his (peace be upon him) saying in the authentic hadith: And in another hadith with similar meaning, there is an addition. They said: "O Messenger of Allah, what do you say about the in-laws (hamu)?" He said: That is a cause of death. And regarding the "hamu" (in-laws), there is disagreement in its interpretation. The correct view is that it refers to the relatives of the husband, such as the brother, maternal uncle, paternal uncle, and the like. It has also been said, in an interpretation that is very strange and contrary to the texts of the Shari'ah, that it refers to the father of the husband. And the father of the husband, as you know, is a mahram, indeed one of the primary mahrams for the wife. Therefore, it is not permissible to interpret "hamu" in the hadith as the father of the husband; rather, they are the relatives of the husband who are not mahrams to the wife. It is not permissible today for a Muslim to be alone with the wife of his brother in religion and in Islam, due to the prohibition of the Messenger (peace be upon him) in many hadiths of being alone with a woman, unless there is a mahram present, or unless the men who are with the woman are righteous men, and not just one person, but three or more. In that case, there is no harm in such seclusion for the woman, because the suspicion that any harm might occur due to their seclusion with her is far away. Yes.
Another questioner: Without the presence of a mahram, out of necessity.

The Shaykh : Ah, that is the case.