Before you enter a house that is not yours, the Quran asks two things of you: ask permission, and greet the people inside 24:27. Privacy is not a modern idea. It was a command fourteen centuries ago.
From the Quran
يَا أَيُّهَا الَّذِينَ آمَنُوا لَا تَدْخُلُوا بُيُوتًا غَيْرَ بُيُوتِكُمْ حَتَّىٰ تَسْتَأْنِسُوا وَتُسَلِّمُوا عَلَىٰ أَهْلِهَا
From the Prophet ﷺ
«إِنَّمَا جُعِلَ الاِسْتِئْذَانُ مِنْ أَجْلِ الْبَصَرِ»
Seen in the prophets
Here the examples come from the house of the Prophet ﷺ himself.
Some guests at the Prophet's house came before the food was ready and stayed long after, talking. He ﷺ was too shy to tell them, so Allah did: "That was troubling the Prophet, and he was shy of you" 33:53.
Abu Musa knocked at 'Umar's door three times, got no answer, and went home. He explained that the Prophet ﷺ taught: if you ask permission three times and it is not given, go back Bukhari 6245.
What it is not
It is not only about doors. Reading someone's messages over their shoulder, opening their bag, posting their photo: these are all ways of walking in uninvited. And if you are told to come back later, go back: "that is purer for you" 24:28.
Today, in practice
Knock before you open any closed door, even at home.
Don't read someone's screen over their shoulder.
Ask before you post a photo of someone else.
Small, practical steps. This is friendly advice, not a ruling.
Your manner for the week
الاِسْتِئْذَان Asking permission
Choose one manner and carry it for seven days. It is saved on this device only, nobody else sees it.
Their moments
Sources on this page
Quran 24:27Quran 33:53Sahih al-Bukhari 6241Sahih al-Bukhari 6245
Quran meanings are given in plain English, close to the Arabic. Hadith numbers follow sunnah.com.