What is the wisdom behind the prohibition of 'zina' (unlawful sexual intercourse) in Islam? And is there anything in the Qur’an or Sunnah that clarifies the reason for its prohibition?

The believer must submit to Allah’s rulings, even if they do not comprehend the wisdom behind them, while having faith that Allah legislated them only for the good of humanity. Allah Almighty says: (The only statement of the believers when they are called to Allah and His Messenger to judge between them is that they say, “We hear and we obey.” And those are the successful).

Nevertheless, there is no impediment to seeking out the wisdom, to increase certainty and to argue with non-Muslims.

Allah has absolutely forbidden zina (unlawful sexual intercourse) and legislated a worldly punishment (the hadd) for it. Among the wisdoms behind its prohibition are:

1. Its congruence with human nature (fitra) and a person's protective jealousy over their honor. 2. Preventing the mixing of lineages. 3. Preserving the family and its cohesion. 4. Protection from dangerous diseases that spread because of it, as confirmed by the Prophet, peace and blessings be upon him, who said: (Whenever Fahishah (immorality) appears in a people to such an extent that they proclaim it, plagues and diseases which were unknown to their forefathers will spread among them). 5. Preserving the dignity of women. 6. Preventing the spread of crimes, as zina is a cause of murder.

Allah has coupled zina with polytheism and the killing of a soul in His saying: (And those who do not invoke with Allah another deity or kill the soul which Allah has forbidden [to be killed], except by right, and do not commit unlawful sexual intercourse. And whoever does that will meet a penalty. The punishment will be doubled for him on the Day of Resurrection, and he will abide therein in humiliation – Except for those who repent, believe and do righteous deeds; for them Allah will change their sins into good deeds. And ever is Allah Forgiving and Merciful), and He forbade it, glorified be He, by saying: (And do not approach unlawful sexual intercourse. Indeed, it is ever an immorality and is evil as a way).