A woman travelling without a mahram
The Messenger of Allaah (peace and blessings of Allaah be upon him) said: “It is not permitted for the woman who believes in Allaah and the Last Day to travel one day’s distance without the presence of a mahram.” (Reported by Muslim, 2/977). When a woman travels without a mahram, this encourages corrupt people to prey on her because of her weakness; at the very least, her honour will be harmed. This prohibition applies also to a woman travelling by plane, even if - as is often claimed - one mahram sees her off at one end and another mahram meets her at the other. Who is going to sit next to her during the journey? What if technical problems divert the plane to another airport, or the flight is delayed? What if...? There are too many stories of things that went wrong. For a person to be considered a mahram, he must meet four conditions: he should be a Muslim, over the age of puberty, of sound mind, and male.
Abu Sa’eed al-Khudri said: “The Messenger of Allaah (peace and blessings of Allaah be upon him) said: ‘No woman who believes in Allaah and the Last Day should travel a distance of three days’ journey or more unless her father, son, husband, brother or other mahram is with her.” (Reported by Muslim, 2/977).
Deliberately looking at a non-mahram woman
Allaah says (interpretation of the meaning):
“Tell the believing men to lower their gaze (from looking at forbidden things), and to protect their private parts (from illegal sexual acts, etc.). That is purer for them. Verily, Allaah is All-Aware of what they do.” [al-Noor 24:30]
The Prophet (peace and blessings of Allaah be upon him) said: "The adultery of the eyes is by looking" (i.e. by looking at what Allaah has forbidden). (Reported by al-Bukhaari, see Fath al-Baari, 11/26). Looking for a legitimate purpose is exempted from this rule, such as looking at a woman for marriage purposes, or a doctor examining a patient for medical reasons, etc. Women are equally forbidden to look at non-mahram men, as Allaah says (interpretation of the meaning):
“And tell the believing women to lower their gaze (from looking at forbidden things) and to protect their private parts (from illegal sexual acts, etc.) . . .” [al-Noor 24:31]
Men are also forbidden to look with desire at a man with a hairless or beautiful face. Men are forbidden to look at the ‘awrah of other men, and women are forbidden to look at the ‘awrah of other women. If it is forbidden to look at something, it is forbidden to touch it, even over clothing. One of the ways in which Shaytaan deceives people is by making them think that there is nothing wrong with looking at pictures in magazines or watching movies, because what is seen is not “real,” even though such images clearly cause so much damage by provoking desires.
Seeing one’s womenfolk behaving in an immoral fashion and keeping silent
Ibn ‘Umar (may Allaah be pleased with him and his father) reported that the Prophet (peace and blessings of Allaah be upon him) said: “There are three whom Allaah will deprive of Paradise: the one who drinks intoxicants, the one who is disobedient to his parents, and the one who accepts immoral conduct on the part of his family.” (Reported by Imaam Ahmad, 2/69; see also Saheeh al-Jaami’, 3047). One of the many examples of this in modern times is men turning a blind eye to their daughters or wives contacting non-mahram men and chatting to them in a way that may be described as “romantic,” or accepting one of the women of his household being alone with a non-mahram man, or allowing them to sit alone with a driver or other employee, or letting them go out without proper hijaab, so that everyone may look at them, or bringing home immoral magazines and movies.
Looking into people's houses without their permission
Allaah says (interpretation of the meaning):
"O you who believe! Enter not houses other than your own, until you have asked permission and greeted those in them . . ." [al-Noor 24:27]
The Prophet (peace and blessings of Allaah be upon him) explained that the reason why permission was to be sought was for fear that the person seeking to enter might see something private in the house: "The rule of seeking permission has been established for the sake of (not) seeing." (Reported by al-Bukhaari, see Fath al-Baari, 11/24). Nowadays, when houses and buildings are too close to one another or even attached, and doors and windows face one another, the possibility of neighbours seeing one another has increased greatly. Many people do not lower their gaze, and some of those who live on higher floors may deliberately look down from their roofs and windows into neighbouring homes that are lower than their own. This is an act of betrayal and an invasion of their neighbours' privacy, as well as being the way that leads to haraam deeds. A great deal of misery and trouble has resulted from this, and that fact that the Sharee'ah counts the eye of the one who spies as worthless is sufficient proof of the seriousness of the matter. The Messenger of Allaah (peace and blessings of Allaah be upon him) said: "Whoever looks into somebody's house without their permission, it is permissible for them to put out his eye." (Reported by Muslim, 3/1699). According to another report, he said: "Put out his eye, and there will be no penalty or retribution." (Reported by Imaam Ahmad, 2/385; see also Saheeh al-Jaami', 6022).
Eavesdropping on people who do not want to be heard
Allaah says (interpretation of the meaning): ". . . And spy not (on one another) . . ." [al-Hujuraat 49:12].
Ibn 'Abbaas (may Allaah be pleased with him) reported that the Prophet (peace and blessings of Allaah be upon him) said: "Whoever listens to people's conversations without their permission will have molten lead poured into his ears on the Day of Resurrection . . ." (Reported by al-Tabaraani in al-Kabeer, 11/248-249; see also Saheeh al-Jaami', 6004).
If this person then goes and tells others of the conversation he overheard in order to cause trouble for them, then his sin of spying is compounded by another sin, as the Prophet (peace and blessings of Allaah be upon him) said: "The eavesdropper will not enter Paradise." (Reported by al-Bukhaari, see Fath al-Baari, 10/472).