In the previous verse Allah (swt) speaks about the rights of orphans, likewise the person who wants to marry an orphan girl, may want to marry her for her money, or because she is a weak woman, Allah (swt) addressing him saying that if you fear that you will not deal justly considering that she is an orphan, or that you may take from her money after you marry her, leave this matter, as you have Lots of options in the matter of marriage, so:

فَانكِحُواْ مَا طَابَ لَكُم مِّنَ النِّسَاء {then marry those that please you of [other] women}: Allah (swt) mentions the unlawful woman that cannot be married in other verse:

حُرِّمَتْ عَلَيْكُمْ أُمَّهَاتُكُمْ وَبَنَاتُكُمْ وَأَخَوَاتُكُمْ وَعَمَّاتُكُمْ وَخَالاَتُكُمْ وَبَنَاتُ الأَخِ وَبَنَاتُ الأُخْتِ وَأُمَّهَاتُكُمُ اللاَّتِي أَرْضَعْنَكُمْ وَأَخَوَاتُكُم مِّنَ الرَّضَاعَةِ وَأُمَّهَاتُ نِسَآئِكُمْ وَرَبَائِبُكُمُ اللاَّتِي فِي حُجُورِكُم مِّن نِّسَآئِكُمُ اللاَّتِي دَخَلْتُم بِهِنَّ فَإِن لَّمْ تَكُونُواْ دَخَلْتُم بِهِنَّ فَلاَ جُنَاحَ عَلَيْكُمْ وَحَلاَئِلُ أَبْنَائِكُمُ الَّذِينَ مِنْ أَصْلاَبِكُمْ وَأَن تَجْمَعُواْ بَيْنَ الأُخْتَيْنِ إَلاَّ مَا قَدْ سَلَفَ إِنَّ اللّهَ كَانَ غَفُورًا رَّحِيمًا

{Prohibited to you [for marriage] are your mothers, your daughters, your sisters, your father’s sisters, your mother’s sisters, your brother’s daughters, your sister’s daughters, your [milk] mothers who nursed you, your sisters through nursing, your wives’ mothers, and your step-daughters under your guardianship [born] of your wives unto whom you have gone in. But if you have not gone in unto them, there is no sin upon you. And [also prohibited are] the wives of your sons who are from your [own] loins, and that you take [in marriage] two sisters simultaneously, except for what has already occurred. Indeed, Allah is ever Forgiving and Merciful.} (An-Nisa: 23)

Hence, the talk is about the orphan girl, if you are afraid that you will not be one hundred percent fair with her, then marry any other woman that is lawful for you:

مَثْنَى وَثُلاَثَ وَرُبَاعَ  { two or three or four }: Arguments were raised about the issue of polygamy, however talking about the polygamy in this verse:

1- It comes in the context of talking about orphans.

2- It is permissible and not obligatory, and this permissibility is limited by justice. You cannot take what is permissible and leave the obligation, which is (justice)

فَإِنْ خِفْتُمْ أَلاَّ تَعْدِلُواْ فَوَاحِدَةً{But if you fear that you will not be just, then [marry only]}: For a man to marry two, three or four, this is the issue. Before Islam and in Western societies, a man would marry an unlimited number of women, and he could have concubines, and the woman was contempt and was considered a tool for pleasure. Islam set controls for this matter. Islam did not impose on any Muslim to marry more than one woman, on the contrary, Islam controls the desires of the people and did not come to release the desires, but it codifying for all cases and for all societies and in all circumstances. Verily, Islam bound polygamy by conditions and reasons that are necessary, but justice must be achieved; Because Allah (swt) says:

{But if you fear that you will not be just, then [marry only]}.

The origin is to marry one woman and more than that is permissible in certain circumstances. Here we must stop at the issue of justice. There is a verse in this Surah that says:

وَلَن تَسْتَطِيعُواْ أَن تَعْدِلُواْ بَيْنَ النِّسَاء وَلَوْ حَرَصْتُمْ فَلاَ تَمِيلُواْ كُلَّ الْمَيْلِ فَتَذَرُوهَا كَالْمُعَلَّقَةِ

{And you will never be able to be equal [in feeling] between wives, even if you should strive [to do so]. So do not incline completely [toward one] and leave another hanging. And if you amend [your affairs] and fear Allah – then indeed, Allah is ever Forgiving and Merciful.}  (An-Nisa: 129)

The non-equality in the verse refers to the equality in feelings.

‘A’isha (PBUH) said that the Prophet (saws) used to divide his time among his wives equally saying:

“O Allah, this is my division concerning what I possess, so do not blame me concerning what you possess and I do not.”[1]

Hence, Allah permitted polygamy in the conditions that are mentioned in the Holy Qur’an. There are cases in societies in which polygamy may be needed, Islam is for all times and all places, so do not say that this is a deficiency in Islam, but it is a deficiency in  understanding the purposes of Islamic law, in applying the rulings of Islam, in adopting permissible things and leaving out the obligations.

أَوْ مَا مَلَكَتْ أَيْمَانُكُمْ {then [marry only] one or those your right hand possesses}: When Islam came, there was a big social issue in all countries of the world that is slavery of the captives, at the same time when the issue of marriage had no limits in pluralism. As for the slavery, Allah (swt) expands the ways of freeing slaves; that is the slave woman becomes free if she gives birth to a boy, which is a condition that exists in societies, and Islam eliminates slavery by permitting marriage from the captive women. Now in societies there is no captive women, so no one is allowed to say about a servant in his house that he possesses her, this is a fraud against the law of Allah (swt). Captive women exist in a society in which there are slaves, and in a society in which there are wars and prisoners are taken as slaves and maidservants, but why this verse is for every time and place? Perhaps after a thousand years’ slavery will return, how do we know! Islam is not for a specific period of time, but for all times. Realizing these facts, when these issues are dealt with in Islamic law, they must be taken with their circumstances, provisions, obligation, permissibility and forbiddance. The matter is not that every time a person wants to unleash his desire, he takes a verse from the Book of Allah (swt) and relies on it.

ذَلِكَ أَدْنَى أَلاَّ تَعُولُواْ {That is more suitable that you may not incline [to injustice]}: To be just in your doing this, the matter of polygamy has become clear, so no one should say: This is an imperative law in the Holy Qur’an, but it is a permissibility bounded with obligation of achieving the justice.

[1] Sunan abi Dawood: Chapter of marriage, Hadith No.2134.