Polygamy vs Monogamy

The law that favorises monogamy leads to a situation where it is unlawful to marry more than one woman. And that leads to...Illegal sexual relations! Well, in some Occidental countries... There are plenty of real-life heartbreaking stories, concerning hidden relations who hurt all the persons involved!

Islam teaches us what is good and forbids us what is evil.
In some cases, polygamy could be favorised over the monogamy.

Here are some verses from Quran:

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Allah commands justice, the doing of good, and liberality to kith and kin, and He forbids all shameful deeds, and injustice and rebellion: He instructs you, that ye may receive admonition. [Coran, 16:90]
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And come not near to unlawful sex. Verily, it is a Fahishah (i.e. anything that transgresses its limits: a great sin), and an evil way (that leads one to Hell unless Allah forgives him). [Coran, 17:32]
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Say (O Muhammad صلى الله عليه وسلم): "(But) the things that my Lord has indeed forbidden are Al-Fawahish (great evil sins and every kind of unlawful sexual intercourse) whether committed openly or secretly, sins (of all kinds), unrighteous oppression, joining partners (in worship) with Allah for which He has given no authority, and saying things about Allah of which you have no knowledge." [Coran, 7:33]
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Men are the protectors and maintainers of women, because Allah has given the one more (strength) than the other, and because they support them from their means. [Coran, 4:34]
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Verily, those who accuse chaste women, who never even think of anything touching their chastity and are good believers - are cursed in this life and in the Hereafter, and for them will be a great torment - [Coran, 24:23]
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Recite (O Muhammad صلى الله عليه وسلم) what has been revealed to you of the Book (the Qur'an), and perform As-Salat (Iqamat-as-Salat). Verily, As-Salat (the prayer) prevents from Al-Fahsha' (i.e. great sins of every kind, unlawful sexual intercourse) and Al-Munkar (i.e. disbelief, polytheism, and every kind of evil wicked deed) and the remembering (praising) of (you by) Allah (in front of the angels) is greater indeed [than your remembering (praising) of Allah in prayers. And Allah knows what you do. [Coran, 29:45]
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You will never be able to do perfect justice between wives even if it is your ardent desire, so do not incline too much to one of them (by giving her more of your time and provision) so as to leave the other hanging (i.e. neither divorced nor married). And if you do justice, and do all that is right and fear Allah by keeping away from all that is wrong, then Allah is Ever Oft-Forgiving, Most Merciful. [Coran, 4:129]
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And if you fear that you shall not be able to deal justly with the orphan-girls then marry (other) women of your choice, two or three, or four; but if you fear that you shall not be able to deal justly (with them), then only one or (the slaves) that your right hands possess. That is nearer to prevent you from doing injustice. [Coran 4:3]
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