Sayyiduna Abu Dharr (may Allah be pleased with him) narrates that the Messenger of Allah (peace and blessings of Allah be upon him) said: "Whoever lifts the curtain (of someone's house) and starts looking inside the house without permission, and sees the private matters of the household, then he has committed such a transgression that is not lawful for him. If (at that moment), while he is looking, someone comes and puts out his eye, I would not blame him for it. However, if a person passes by a door that has no curtain and is not closed, then there is no sin on the one who looks inside such a house, but the sin will be upon the household."