[23].Surah Al-Muminun [The Believers]: Ayat 1-5

Ayat 1. Successful indeed are the believers.
Ayat 2. Those who offer their Salat (prayers) with all solemnity and full submissiveness.
Ayat 3. And those who turn away from Al-Laghw (dirty, false, evil vain talk, falsehood, and all that Allah has forbidden).
Ayat 4. And those who pay the Zakat. Ayat 5. And those who guard their chastity (i.e. private parts, from Zina adultery illegal acts & relationship without matrimonial).

[Tafseer] The believers must (eventually) win through, Aflaha: win through, prosper, succeed, achieve their aims or obtain salvation from sorrow and all evil. This verse connects on with verses 10 and 11 of this Surah. The success or victory may come in this world, but is certain and lasting in the world to come. 2. Those who humble  themselves in their prayers; Humility in prayer as regards (1) their estimate of their own worth in Allah's presence, (2) as regards their estimate of their own powers or strength unless they are helped by Allah, and as regards the petitions they offer to Allah. 3. Who avoid vain talk; 4. Who are active in deeds of charity; 5. Who abstain from Zina adultery (relationship without matrimonial), The Muslim must guard himself against ever;' kind of Zina adultery (relationship without matrimonial) abuse or perversion. The new psychology associated with the name of Freud traces many of our hidden motives to Zina adultery (relationship without matrimonial) and it is common knowledge that our refinement or degradation may be measured by the hidden workings of our Zina adultery instincts. But even the natural and lawful exercise of Zina adultery (relationship without matrimonial) is restricted to the marriage bond, under which the rights of both parties are duly regulated and maintained.

Hazrat Abu Hurairah (May Allah be pleased with him) reported: The Messenger of Allah [SAWW](PBUH) said, "Allah has written the very portion of Zina which a man will indulge in. There will be no escape from it. The Zina of the eye is the (lustful) look, the Zina of the ears is the listening (to voluptuous songs or talk), the Zina of the tongue is (the licentious) speech, the Zina of the hand is the (lustful) grip, the Zina of the feet is the walking (to the place where he intends to commit Zina), the heart yearns and desires and the private parts approve all that or disapprove it.''

[Muslim Book 33, Chapter 05, Hadith # 6422]

Lesson : as mentioned above in Surah Al-Muminun Ayat 05."And those who guard their chastity (i.e. private parts, from Zina" Seeing, listening, walking, etc., are means of committing the sin of fornication and adultery, but they have been termed so metaphorically so that every Muslim saves himself from them. If he does not try to save himself from them, his desires will find support from the private parts of his body; that is, he will incline to immoral acts. If he keeps himself away from the means of fornication and adultery, his private parts will crush his desires, that is to say he will be saved from immoral acts. This is the reason it is said that one should avoid glances, smiles, salutation, conversation, promises and then meetings which occur by stages on one's way to fornication and adultery.