Assalamu alaykum. Is it obligatory to give the Salaam greeting and take permission before entering my relatives' house? Sometimes they open the door for me and I just enter without asking permission orally. Is that a sin?

All perfect praise be to Allah, the Lord of the worlds. I testify that there is none worthy of worship except Allah and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.

The basic principle is that it is obligatory to seek permission before entering. Allah, the Exalted, says (what means): {O you who have believed, do not enter houses other than your own houses until you ascertain welcome and greet their inhabitants...} [Quran 24:27]

The Kuwaiti Encyclopedia of Fiqh reads, "The scholars of Fiqh unanimously agreed that it is impermissible to enter someone's house except with permission."

The obligation in this regard is not waived merely because the door is open, as was stated by the scholars. Al-Qurtubi commented on the above-mentioned verse saying, "This applies whether the door is closed or open, because the Shariah deemed it closed by the prohibition to enter until the permission of the inhabitants opens it. Rather, the visitor should stand by the door and seek permission to enter while being careful not to look inside the house as he moves towards it or moves away from it."

Hence, not entering even if the door is open is the principle ruling; however, scholars gave concession to the Mahram (permanently unmarriageable) relative, especially one who does not live with them in the house, that if he finds the door open he may go in without permission along with making them aware of his entrance by clearing his throat or making any noise.

The Shaafiʻi scholar Al-Maawardi said in his book Al-Haawi,

"If a Mahram relative wants to enter the house, there are two possible cases:

First: if this Mahram relative lives with the owners of the house; he is not obliged to seek permission, but he should make his entrance known by clearing his throat or taking heavy steps so that the people inside the house would cover themselves if they are undressed and the like.

Second: if the Mahram relative does not live with the owners of the house; if the door is closed, he may not enter except with permission. If the door is open, there are two scholarly views regarding the obligation of seeking permission before entering the house in this case:

The first is that he is obliged to seek permission, and it is prohibited for him to enter the house without the permission of the home owner because it is possible that the latter is undressed. The Prophet, sallallaahu ‘alayhi wa sallam, said, 'Seeking permission was enjoined because of the sight (so that one should not look at what he is not supposed to see of others).'

The second is that he is not obliged to seek permission; however, he is required to make his entrance felt by clearing his throat or any movement. Allah, the Exalted, says (what means): {There is not upon the blind (any) constraint nor upon the lame constraint nor upon the ill constraint nor upon yourselves when you eat from your (own) houses or the houses of your fathers or the houses of your mothers or the houses of your brothers or the houses of your sisters or the houses of your father's brothers or the houses of your father's sisters ...} [Quran 24:61] The verse made a distinction between the Mahram relatives and the non-Mahram ones in terms of permissibility (of entering without permission)."

Some contemporary scholars stated that if the visitor knows that the door was opened for him and that those inside the house are expecting him, there is no blame on him in entering even without seeking permission because they have already given him permission by leaving the door open for him.

Shaykh Ibn ʻUthaymeen said:

"The verse says {until you ascertain welcome}, which means that you seek permission or you know with certainty that those inside the house are ready to receive you. For instance, if someone invites you over to his house and asks you to come after the Thuhr prayer, then if you come and find the door open, then he has given you permission to enter. So there is no need for you to seek permission because he invited you and asked you to come at that specific time. If you find the door open, this is a valid permission, and it does not matter whether the permission is issued prior to or after the guest's arrival. As long as you know that he has not left his door open except for you to enter and you have an arranged appointment, you are allowed to enter the house. However, it is better, without doubt, to greet the people inside the house with the Salaam, even if done merely for the sake of earning the rewards of greeting others and having them supplicate Allah in your favor when they answer your greeting by saying, 'wa ‘alayk assalaam (and peace be upon you).'"

Allah knows best.