Short answer
The Quran treats desire as part of human nature (3:14) but tells you to control it: lower your gaze and guard your private parts (24:30 to 31), do not even approach zina (17:32), and fulfil desire only through marriage. The Sunnah adds marriage for those who can, and fasting for those who cannot.
Looking with desire at a non-mahram is haram, and an unintended first glance is forgiven if you look away. Acting on lust outside marriage, and the steps that lead to it, are haram. Marriage is sunnah in normal circumstances and wajib for someone who fears falling into zina and can afford it.
The four schools agree on this.
Explanation
Desire is natural. "Beautified for people is the love of that which they desire: of women and sons, heaped-up sums of gold and silver..." (3:14). The Quran does not call desire itself evil. It calls these things the enjoyment of this world and reminds you that what is with Allah is better.
The Quran's guidance:
- Lower the gaze: "Tell the believing men to reduce some of their vision and guard their private parts. That is purer for them" (24:30), and the same for believing women in the next ayah. The gaze is where lust usually starts, which today includes screens.
- Keep away from the path to zina: "Do not approach unlawful sexual intercourse" (17:32). Not only zina is forbidden but also what leads to it: private meetings, flirting and explicit content.
- Marriage: the Quran describes spouses as a source of tranquillity, love and mercy (30:21).
- Self-restraint is praised: those who guard their private parts are among the successful believers (23:5).
The Prophet ﷺ told young people that whoever can afford marriage should marry, since it lowers the gaze and protects chastity, and whoever cannot should fast. He also said that the eyes and the tongue have their share of zina, so the struggle starts long before the act. A slip is not the end: Allah forgives the one who repents sincerely. See how to repent, falling in love before marriage and nikah.
The evidence
Quran, Surah Aal-i-Imraan 3:14
زُيِّنَ لِلنَّاسِ حُبُّ ٱلشَّهَوَٰتِ مِنَ ٱلنِّسَآءِ وَٱلْبَنِينَ وَٱلْقَنَٰطِيرِ ٱلْمُقَنطَرَةِ مِنَ ٱلذَّهَبِ وَٱلْفِضَّةِ وَٱلْخَيْلِ ٱلْمُسَوَّمَةِ وَٱلْأَنْعَٰمِ وَٱلْحَرْثِ ۗ ذَٰلِكَ مَتَٰعُ ٱلْحَيَوٰةِ ٱلدُّنْيَا ۖ وَٱللَّهُ عِندَهُۥ حُسْنُ ٱلْمَـَٔابِ ﴿١٤﴾
Beautified for people is the love of that which they desire - of women and sons, heaped-up sums of gold and silver, fine branded horses, and cattle and tilled land. That is the enjoyment of worldly life, but Allah has with Him the best return.
Desire is part of human nature.
Quran, Surah An-Noor 24:30
قُل لِّلْمُؤْمِنِينَ يَغُضُّوا۟ مِنْ أَبْصَٰرِهِمْ وَيَحْفَظُوا۟ فُرُوجَهُمْ ۚ ذَٰلِكَ أَزْكَىٰ لَهُمْ ۗ إِنَّ ٱللَّهَ خَبِيرٌۢ بِمَا يَصْنَعُونَ ﴿٣٠﴾
Tell the believing men to reduce [some] of their vision and guard their private parts. That is purer for them. Indeed, Allah is Acquainted with what they do.
The command to lower the gaze and guard chastity.
Quran, Surah Al-Israa 17:32
وَلَا تَقْرَبُوا۟ ٱلزِّنَىٰٓ ۖ إِنَّهُۥ كَانَ فَٰحِشَةًۭ وَسَآءَ سَبِيلًۭا ﴿٣٢﴾
And do not approach unlawful sexual intercourse. Indeed, it is ever an immorality and is evil as a way.
Forbids not only zina but approaching it.
Sahih al-Bukhari 5066
Sahih... يا معشر الشباب من استطاع منكم الباءة فليتزوج ...
"O young people, whoever of you can afford marriage should marry, for it lowers the gaze and guards chastity; whoever cannot should fast."
Marriage and fasting are the prophetic remedies for strong desire.
Sahih al-Bukhari 6243
Sahih... إن الله كتب على ابن آدم حظه من الزنا ...
"Allah has written for the son of Adam his share of zina: the zina of the eyes is looking, and the zina of the tongue is speech."
Lust begins with the eyes and words, so control starts there.
Sahih Muslim 2159
Sahih... سألت رسول الله صلى الله عليه وسلم عن نظر الفجاءة فأمرني أن أصرف بصري ...
"Jarir said: I asked the Messenger of Allah about the sudden glance, and he told me to turn my eyes away."
The first accidental glance is excused; continuing to look is not.
Where the ruling is recorded
- al-Hidaya, Kitab al-Karahiyya, chapter on looking and touching. Rules on looking at non-mahrams and looking with desire.
- al-Durr al-Mukhtar, Kitab al-Nikah, opening section. Marriage becomes wajib for one who fears zina and can pay the mahr and maintenance.
Checked by our team. For a more accurate answer to your own situation, consult a scholar. Quran translation by Sahih International. Hadith Arabic from the standard editions of the six books and the Muwatta, with gradings as recorded there; the English is our own rendering. Spotted a mistake? Tell us.