4:3 - And if you fear that you will not deal justly with the orphan girls, then marry those that please you of [other] women, two or three or four. But if you fear that you will not be just, then [marry only] one or those your right hand possesses. That is more suitable that you may not incline [to injustice].
Verse 3 states that though it is advisable to marry from the orphan girls, one may do so if one is sure of doing full justice to them. Else marry any other girl. One may marry upto a limit of 4, but if one is not sure of treating all of them equally, then it is better to marry only one woman from any believing woman or from any believing woman from the slaves (There was a practice of slavery those days.... in place of servants). Marrying one woman, if fearing injustice to them is highlighted again in the last sentence as Allah does not like those who do injustice to others.
This point is further stressed through verse 129 which states that no man can be equal to more than one woman, no matter how much he tries.....
4:129 - 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.
In the act of being more favourable to one wife, man is likely to be unjust towards his other wife/ wives. So instead of being in such a situation, wherein the man is not able to be just to one wife (by dividing time and money) equally among them, then it is better to separate by settlement.
4:130 - But if they separate [by divorce], Allah will enrich each [of them] from His abundance. And ever is Allah Encompassing and Wise.
Bridal gifts (Mahr):
Women are entitle to a marriage gift from their husbands at the time of marriage (but this should be what the guy can afford). This is reverse of the law in some countries, where men are ask money (dowry) from women for marriage, whether they can afford it or not. This is also followed up by beating or killing the bride eventually to meet dowry demands...
4:4 - And give the women [upon marriage] their [bridal] gifts graciously. But if they give up willingly to you anything of it, then take it in satisfaction and ease.
The mahr cannot be taken back, unless wife gives it up willingly. This is so even after a divorce is sought....
4:20 - But if you want to replace one wife with another and you have given one of them a great amount [in gifts], do not take [back] from it anything. Would you take it in injustice and manifest sin?
4:21 - And how could you take it while you have gone in unto each other and they have taken from you a solemn covenant?
WOMEN'S RIGHTS IN PROPERTY :
4:7 - For men is a share of what the parents and close relatives leave, and for women is a share of what the parents and close relatives leave, be it little or much - an obligatory share.
4:8 - And when [other] relatives and orphans and the needy are present at the [time of] division, then provide for them [something] out of the estate and speak to them words of appropriate kindness.
This is an appeal to make provision for needy people from your property
4:9 - And let those [executors and guardians] fear [injustice] as if they [themselves] had left weak offspring behind and feared for them. So let them fear Allah and speak words of appropriate justice.
This verse calls for justice from the guardians/ witnesses / executors of the will.
4:10 - Indeed, those who devour the property of orphans unjustly are only consuming into their bellies fire. And they will be burned in a Blaze.
This again is a warning for custodians of orphan's property (left by their parents / guardians) till they come of age.
The following verses state how the property (in absence of will) is to be distributed among family :
4:11 - Allah instructs you concerning your children: for the male, what is equal to the share of two females. But if there are [only] daughters, two or more, for them is two thirds of one's estate. And if there is only one, for her is half. And for one's parents, to each one of them is a sixth of his estate if he left children. But if he had no children and the parents [alone] inherit from him, then for his mother is one third. And if he had brothers [or sisters], for his mother is a sixth, after any bequest he [may have] made or debt. Your parents or your children - you know not which of them are nearest to you in benefit. [These shares are] an obligation [imposed] by Allah . Indeed, Allah is ever Knowing and Wise.
4:12 - And for you is half of what your wives leave if they have no child. But if they have a child, for you is one fourth of what they leave, after any bequest they [may have] made or debt. And for the wives is one fourth if you leave no child. But if you leave a child, then for them is an eighth of what you leave, after any bequest you [may have] made or debt. And if a man or woman leaves neither ascendants nor descendants but has a brother or a sister, then for each one of them is a sixth. But if they are more than two, they share a third, after any bequest which was made or debt, as long as there is no detriment [caused]. [This is] an ordinance from Allah , and Allah is Knowing and Forbearing.
4:13 - These are the limits [set by] Allah , and whoever obeys Allah and His Messenger will be admitted by Him to gardens [in Paradise] under which rivers flow, abiding eternally therein; and that is the great attainment.
4:19 - O you who have believed, it is not lawful for you to inherit women by compulsion. And do not make difficulties for them in order to take [back] part of what you gave them unless they commit a clear immorality. And live with them in kindness. For if you dislike them - perhaps you dislike a thing and Allah makes therein much good.
Points highlighted in this verse :
1) Women cannot be forced for marriage or by becoming heirs to their property.
3) Women should be treated kindly
4) If you dislike your wife, so it is possible that you dislike a thing in which Allah has placed abundant good.
Who are the women prohibited in marriage to a man ? This is clearly mentioned in verses 23 and 24 as below :
4:23 - 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.
4:24 - And [also prohibited to you are all] married women except those your right hands possess. [This is] the decree of Allah upon you. And lawful to you are [all others] beyond these, [provided] that you seek them [in marriage] with [gifts from] your property, desiring chastity, not unlawful sexual intercourse. So for whatever you enjoy [of marriage] from them, give them their due compensation as an obligation. And there is no blame upon you for what you mutually agree to beyond the obligation. Indeed, Allah is ever Knowing and Wise.
Who can be married and conditions of marriage....
4:25 - And whoever among you does not have means to marry free, believing women due to poverty, should marry from the believing bondwomen you own; and Allah knows well your faith; you are from one another; therefore marry them with the permission of their masters/ people, and give them their bridal money according to custom, they becoming (faithful) wives, not committing mischief or secretly making friends; so when they are married and commit the shameful, for them is half the punishment prescribed for free women; this is for one among you who fears falling into adultery; and to practice patience is better for you; and Allah is Oft Forgiving, Most Merciful.
Equality between men and women...
4:32 - And do not long for things by which Allah has given superiority to some of you over others; for men is the share of what they earn; and for women the share from what they earn; and seek from Allah His munificence; indeed Allah knows everything.
Here it is highlighted that one should not just long or pray for some thing/s which is granted to another (by comparing ourselves with others) because men and women get what they earn for themselves.