As stated in the first part, Islam brought about reforms in the customs previous nations, including Arabs, had in practicing polygamy in Islam:

The Limitation in the Polygamy in Islam

The first reform Islam enforced was the restriction it imposed upon polygamy. Before the advent of Islam, there was no limit to the number of wives. One man could keep hundreds of wives and thus establish a harem for them, just as the ones some kings had, which is strictly banned in the religion of Islam.

However, Islam put a maximum limit on their number, and an individual was not allowed to have more than four wives simultaneously.

Justice:

The other reform that was made upon polygamy in Islam was the condition under which there must never be, for any reason, discrimination between the wives or their children. The Holy Quran explicitly commands:

"But if you fear that you may not treat them fairly, then [marry only] one" (4:3)

As a matter of fact, those men who can observe full justice with a number of wives are very few. It is clearly stated in the following verse of the Quran which is in association with the previous verse:

"you will not be able to be fair between wives, even if you are eager to do so..." (4:129)

Allah explains here that justice between the wives in its true sense - to stand exactly in the middle of the extremes - is beyond human power even if one may wish it. What a man is obliged to do is that he should not be totally inclined to one of them, leaving the other one as she were in suspense… [1].

Other conditions for Polygamy in Islam

Besides these two main restrictions, there are other responsibilities and duties polygamous men have to fulfill toward all their wives; such as Nafaqah (alimony) and Mahrieh (marriage portion), etc. [see the article about the rights of the wife over her husband]

The Best Form of Marriage in Islam

Ultimately, there is no dispute about the fact that monogamy is better; it is actually the best and most natural form of marriage in Islam. Obviously, the spirit of marital life which is oneness and unity is attained better and with more perfection with a single spouse.

It is only within this form of marriage that family commitment makes sense, and the great bond that unites the hearts of husband and wife makes them become one soul and one flesh [2].

Polygamy in Islam, on the other hand, rises from a social problem that rests heavily on the shoulders of all men and married women and for which a better solution has not yet been found. We have to face the fact that monogamy is not practical in specific social circumstances, and polygamy -under the mentioned conditions- is the most significant saving factor for monogamy.

A Choice between Conflicting Alternatives

One of two alternatives should be chosen: either the restricted acceptance of polygamy -as a duty rather than pleasure-, or the love affairs system, which is common in some societies these days. In other words, a few married men should marry more than one wife -of course under the condition of fulfilling all the above-mentioned responsibilities of a husband in a polygamous family-, and these will certainly not exceed a few percents, and unmarried women should settle, get home and make a life for themselves; or else open the way for love affairs.

In the case of the second alternative, the women deprived of family life may associate at her own free will with several men, and, as a result, almost all married men will in practice be polygamists.

Even then the matter will not end. The wives who will find their husbands to be unfaithful will think of taking revenge upon them and thus will themselves become unfaithful. This final result has been summarized in the well-known Kinsey report in one sentence: “The men and women of America have surpassed all other nations in unfaithfulness” [3].

Now, which alternative do you think is better?

References:

1. polygamy
2. Morteza Motahari, women and her rights in Islam, p. 148
3. Morteza Motahari, women and her rights in Islam, p. 150
4. polygamy in islam

“And of His signs is that He created for you from yourselves mates that you may find tranquility in them, and He placed between you affection and mercy. Indeed, in that are signs for a people who give thought.” (30:21)

The concept of marriage is very ancient dating back beyond Abrahamic religions and recorded history and was practiced by all people of many cultures, religions, and ethnicities throughout the earth.  Among all belief systems, Islam is the only religion that accords great importance to marriage and humans’ marital life.

The religion of Islam holds that the progress and development in all aspects of a person’s life roots in how his/her family is formed. Therefore, it provides the people who are ready for committing themselves to marriage with a comprehensive guideline.

Guidelines for choosing a spouse in Islam

Having faith and piety

According to Islam, the first criterion of the most eligible person to marry is having faith and being pious; In other words, the candidate should have a firm belief in Allah and the principles of Islam. This characteristic is so important that without it no other criteria is worthy of attention.

The holy Quran says: “And do not marry polytheistic women until they believe. And a believing slave woman is better than a polytheist, even though she might please you. And do not marry polytheistic men [to your women] until they believe. And a believing slave is better than a polytheist, even though he might please you” (2:221).

If a person believes in God and whatever He commands him/her to do, consequently he/she will not be seduced by temptations of Satan, will be totally devoted to his/her own family and observant of his/her behavior towards them, and will treat his/her spouse and the whole family fairly.

Morality

Another important feature in evaluating the suitable person for marriage is being good-tempered and following the codes of morality in his/her behavior. This characteristic has been defined as “being modest, well-spoken and good-natured” [1] by Imam Sadeq (AS).

Nevertheless, acting morally is not only restricted to being good-tempered but includes honesty, chastity, using decent language, forbearance, politeness, contentment, benevolence, faithfulness, and generosity as well. The presence of morality in one’s behavior is so vital that when Imam Reza (AS) was asked for his advice in marrying a person who was famous for being ill-natured, he strongly disagreed [2].

The nobility of the family

It is stressed in the religion of Islam that one should choose her/his spouse from a decent and noble family. Family nobility does not mean fame, wealth, or social status; rather it means modesty, chastity, purity, and religiousness, which will be all passed on to the next generations.

The Messenger of Allah (PBUH&HP) has said in this regard: “Marry in the lap of a decent family, since the semen and the genes have an effect.” [3]. He has also said to avoid the greenery (herbs) growing over a sewer (cesspool); i.e., a beautiful woman born and raised in an indecent family [4].

Compatibility

Islam also lays special emphasis on compatibility in marriage. The marrying partners must be Kufw of each other; i.e., they should be equal and close to one another in terms of religiosity and morality, as well as social, financial, and also physical aspects. Spouses in the Quran are likened to clothing: “They are clothing for you, and you are clothing for them” (2:187). Just like clothes that should be of the right size, color, and material to suit you well, your spouse has to be a suitable match for you. But do not forget that in the Islamic view, the main point of similarity is in the couple’s belief and faith. Prophet Muhammad (PBUH&HP) has said: “a faithful man is suitable for a faithful woman and a Muslim man is good for a Muslim woman” [5].

Someone who is inferior in faith to you may degrade your belief as well. Marriage is a means of the elevation of the soul, so if it results in the opposite way the whole purpose of this holy union will be wasted.

Physical and Mental health

Although health problems do not preclude marriage, they have negative effects on the continuation of married life. There are various narrations in the Islamic teachings on the importance of marrying someone healthy and of sane state of mind: “when you intend to marry a woman, ask about her physical characteristics since this will create a bond of affection and love between you and your spouse” Prophet Muhammad (PBUH&HP) [6].

It has also been narrated from him that “Avoid marrying a stupid person since her/his company is a woe” [7]. Moreover, we are advised by him to reject the proposal of a person who is accustomed to drinking alcohol for its detrimental effects on the body and soul.

It is noteworthy that there are other features for choosing the right person to marry like financial matters, age differences, racial differences, etc. Though there is a lot of psychological and religious advice on these issues as well, they are not of much importance in Islam as long as the girl and the boy are Muslims and have taken the five above-mentioned significant aspects into consideration.

Allah has promised to fulfill the other needs of the married couple Himself: “And marry the unmarried among you and the righteous among your male slaves and female slaves. If they should be poor, Allah will enrich them from His bounty, and Allah is all-Encompassing and Knowing” (24:32)

References:

1. Usul Al-Kafi , v. 2, p.563
2. Wasa’il ul-Shi’a, v. 14, p.54
3. Makaremul Akhlaq, v. 1, p. 432
4. Al-Kafi, v. 5, p. 332
5. Wasa’il ul-Shi’a, Vol. 14 , p.44
6. Shaikh al-Hur al-Aamili, Wasa’il ul-Shi’a, chapter 35
7. Al-Jafariat, p. 92
8. Choose a Spouse in Islam