Why does Islam allow Polygamy?

“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 captives and the slaves) that your right hands possess. That is nearer to prevent you from doing injustice.” [1] Quran(4:3) Muhsin Khan translation

In Islam, a man is permitted to marry more than one wife only if he was the physical and financial capability to do so. And he also needs to treat all of them justly.

However if he fears he can’t do none of the above then he has to marry only one. The verse above makes this clear.

Muhammad Asad comments on this verse by affirming this

“As regards the permission to marry more than one wife (up to the maximum of four), it is so restricted by the condition, “If you have reason to fear that you might not be able to treat them with equal fairness, then marry only one,” as to make such plural marriages possible only in quite exceptional cases and under exceptional circumstances.” [2] Message of the Quran, verse 4:3

Interestingly Allah says in the following verse that you cannot equally give all of the wives perfect justice giving us a indication that it is encouraged to marry only one.

“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. ” [3] Quran(4:129) Muhsin Khan translation

Muhammad Asad comments on this verse saying

“This refers to cases where a man has more than one wife – a permission which is conditional upon his determination and ability to “treat them with equal fairness,” as laid down in verse 3 of this surah… In view of the fact that a man’s behavior towards another person is, in the long run, almost inevitably influenced by what he feels about that person, the above passage – read in conjunction with verse 3, and especially its concluding sentence – imposes a moral restriction on plural marriages.” [4] Message of the Quran, verse 4:129

Shaykh Muhammad bin Saalih Al-Uthaymeen says

“Marrying more than one wife is a desirable thing – on condition that the man has the financial means and the physical ability to act with justice between his wives. This is because through plurality of wives, good is acheived, such as protecting the private parts of the women who he marries (from illegal sexual intercourse) and broadening of unity between the people, and increasing the number of births, as indicated by the Prophet sallallaahu alahi wasallam: ‘Marry loving, productive women.’ (Abu Dawud 2050, An-Nasaai’ 3229, Ibn Hibbaan 4028, & Ahmad 3/158-245) It also contains many other benefits. As for a man marrying more than one wife out of pride and competitiveness, it is something which falls into the category of waste, which is not permitted. Allaah, the Most High says:’Waste not by extravagance, certainly He (Allaah) likes not Al-Musrifun (those who waste by extravagance).’ (Al-‘Araaf 7:31)” [5] Fatawa Islamiyah, Darussalam, volume 5, page 355-356

So we can clearly see that Islam does not permit polygamous marriages if it merely out of pride or competitiveness.

It only permits them if one has the physical and financial means while also having the requirement to treat them all with equal justice.

However if one fails to have all of the above requirements then marrying only wife is the only available option.

Polygyny is also present in other religions as well.

Christianity has a history of polygamous marriage being permitted in the church.

” It is of indisputed historic record that both the Christian Church and the Christian State in different centuries and under a number of differing circumstances gave their influence in favor of polygamy. The Roman emperor, Valentinian I., in the fourth century, authorized christians to take two wives; in the eighth century the great Charlemagne holding power over both church and state, in his own person practiced polygamy, having six, or according to some authorities, nine wives. With the Reformation this system entered Protestantism. As the first synod in North America was called for the purpose of trying a woman for heresy, so the first synod of the reformation was assembled for the purpose of sustaining polygamy, thus farther debasing woman in the marital relation. The great German reformer, Luther, although perhaps himself free from the lasciviousness of the old priesthood was not strictly monogamic in principle. When applied to by Philip, Landgrave of Hesse Cassel, for permission to marry a second wife while his first wife, Margaret of Savoy, was still living, he called together a synod of six of the principal reformers–Melancthon and Bucer among them–who in joint consultation decided “that as the Bible nowhere condemns polygamy, and as it has been invariably practiced by the highest dignitaries of the church,” such marriage was legitimate, and the required permission was given.” [6] Woman,Church And State by Matilda Joslyn Gage pg 398-399

It was and also still is present in Hinduism

“There is no sin in this. For a man polygamy is an act of merit, but for a woman it is very sinful to betake herself to a second husband after the first.” [7] Mahabharata 1.160.36 (K.M. Ganguli Translation)

“Oh, let Vijaya, let him that is called Gudakesa, let this hero with reddish eyes, come back O life. O blessed lady, polygamy is not fault with men. Women only incur fault by taking more than one husband.” [8] Mahabharata 14.80.12-18 (K.M. Ganguli Translation)

Swami Vivekananda a Hindu scholar finds no problem with Polygamy,

“For women, they hold chastity as the most important virtue, no doubt. One man marrying more than one wife is not so injurious to society as a woman having more than one husband at the same time, for the latter leads to the gradual decay of the race.” [9] The Complete Works of Swami Vivekananda/Volume 5/Writings: Prose and Poems/The East and The West/France-Paris
https://en.wikisource.org/wiki/The_Complete_Works_of_Swami_Vivekananda/Volume_5/Writings:_Prose_and_Poems/The_East_and_The_West/France-Paris

Swami Prabhupada the founder of ISKCON on Polygamy,

“…According to our Vedic process, polygamy is allowed. For example, Krsna married 16,000 wives, Arjuna married 3 or 4 wives, Krsna’s father Vasudeva, married 16 or 18 wives, like that. So according to the Vedic system polygamy is not prohibited…” [10]

By Swami Prabhupada, Letter to Karandhara written from Bombay
http://vanisource.org/wiki/730109_-_Letter_to_Karandhara_written_from_Bombay

He also writes,

“A man is allowed to keep more than one wife because he cannot enjoy sex when the wife is pregnant. If he wants to enjoy sex at such a time, he may go to another wife who is not pregnant. These are laws mentioned in the Manu-samhita and other scriptures” [11]

Swami Prabhupada on Srimad Bhagavatam 4.27.5
http://vanisource.org/wiki/SB_4.27.5

Sources:

[1] Quran(4:3) Muhsin Khan translation

[2] Message of the Quran, verse 4:3

[3] Quran(4:129) Muhsin Khan translation

[4] Message of the Quran, verse 4:129

[5] Fatawa Islamiyah, Darussalam, volume 5, page 355-356

[6] Woman,Church And State by Matilda Joslyn Gage pg 398-399

[7] Mahabharata 1.160.36 (K.M. Ganguli Translation)

[8] Mahabharata 14.80.12-18 (K.M. Ganguli Translation)

[9] The Complete Works of Swami Vivekananda/Volume 5/Writings: Prose and Poems/The East and The West/France-Paris
https://en.wikisource.org/wiki/The_Complete_Works_of_Swami_Vivekananda/Volume_5/Writings:_Prose_and_Poems/The_East_and_The_West/France-Paris

[10] By Swami Prabhupada, Letter to Karandhara written from Bombay
http://vanisource.org/wiki/730109_-_Letter_to_Karandhara_written_from_Bombay

[11] Swami Prabhupada on Srimad Bhagavatam 4.27.5
http://vanisource.org/wiki/SB_4.27.5