Is it permissible for a man and a woman who are not married to each other to engage in "nikah" [marriage ceremony] if they have known each other for a long time and have the approval of both families (such as an engaged couple or close friends)?

The Sacred Law has not made any path for satisfying the sexual urge except through lawful marriage, for which there is no alternative today, after slave-ownership was permitted. As for one who cannot marry, he must practice abstinence and fast, for the Prophet, peace and blessings be upon him, said: "O young men, whoever among you can afford to marry, let him marry, for it helps him lower his gaze and guard his chastity. And whoever cannot afford to marry, let him fast, for it will be a shield for him."

As for the Almighty's saying: "And whoever among you cannot afford to marry free, believing women, then [let him marry] from those whom your right hands possess of your believing slave girls," the term "girls" here refers to slave-girls. It is permissible for a free man to marry a slave-girl with her master's permission, on condition that he is unable to marry a free Muslim woman and fears falling into sin.

Patience regarding marriage is better than marrying a slave-girl. If he is able to marry a chaste, honorable woman from the People of the Book, it is not permissible for him to marry a slave-girl. The Sacred Law has emphasized this due to the consequent enslavement of the child, for "the child follows its mother in freedom or slavery."

As for the Almighty's saying: "And those who follow [their] desires wish that you would deviate [from the straight path] with a great deviation," the intended alleviation refers to marrying slave-girls in times of poverty, or to alleviation in religious obligations generally. However, to permit fornication under the pretext of alleviation is part of the great deviation desired by the followers of desires among disbelievers and fornicators, to drag people towards it. Deviation is turning away from the straight path.