At-Talaq is not only the name of this Surah but also the title of its subject matter, for it contains commandments about Talaq (divorce) itself. Hadrat \`Abdullah bin Mas\`ud has described it as Surah an-Nisa al-qusra also, i.e. the shorter Surah an-Nisa.
Hadrat Abdullah bin Masud has Pointed out, and the internal evidence of the subject matter of the Surah confirms the same, that it must have been sent down after those verses of surah Al-Baqarah in which commandments concerning divorce were given for the first time. Although it is difficult to determine precisely what is its exact date of revelation, yet the traditions in any case indicate that when the people started making errors in understanding the commandments of Surah Al-Baqarah, and practically also they began to commit mistakes, Allah sent down these instructions for their correction.
In order to understand the commandments of this Surah, it would be useful to refresh one's memory about the instructions which have been given in the Qur'an concerning divorce and the waiting period (Iddat) above.
"Divorce may be pronounced twice; then the wife may either be kept back in fairness or allowed to separate in fairness." (Al Baqarah 229)
"And the divorced women (after the pronouncement of the divorce) must wait for three monthly courses... and their husbands are fully entitled to take them back (as their wives) during this waiting period, if they desire reconciliation." (Al Baqarah 228)
"Then, if the husband divorces his wife (for the third time), she shall not remain lawful for him after this divorce, unless she marries another husband..." (Al-Baqarah : 230)
"When you marry the believing women, and then divorce them before you have touched them, they do not have to fulfill a waiting period, the completion of which you may demand of them." (Al-Ahzab : 49)
"And if those of you who die, leave wives behind, the women should abstain (from marriage) for four months and ten days." (Al-Baqarah 234)
The rules prescribed in these verses were as follows:
A man can pronounce at the most three divorces on his wife.
In case the husband has pronounced one or two divorces he is entitled to keep the woman back as wife within the waiting period and if after the expiry of the waiting period the two desire to re-marry, they can re- marry there is no condition of legalization (tahlil). But if the husband has pronounced three divorces, he forfeits his right to keep her as his wife within the waiting. period, and they cannot re-marry unless the woman re-marries another husband and he subsequently divorces her of his own free will.
The waiting period of the woman, who menstruates and marriage with whom has been consummated, is that she should pass three monthly courses. The waiting period in case of one or two divorces is that the woman is still the legal wife of the husband and he can keep her back as his wife within the waiting period. But if the husband has pronounced three divorces, this waiting period cannot be taken advantage of for the purpose of reconciliation, but it is only meant to restrain the woman from re-marrying another person before it comes to an end.
There is no waiting. period for the woman, marriage with whom has not been consummated, and who is divorced even before she is touched. She can re-marry, if she likes, immediately after the divorce.
The waiting period of the woman whose husband dies, is four months and ten days.
Here, one should understand well that Surah At-Talaq was not sent down to annul any of these rules or amend it, but it was sent down for two purposes;
First, that the man who has been given the right to pronounce divorce should be taught such judicious methods of using this right as do not lead to separation, as far as possible however, if separation does take place, it should only be in case all possibilities of mutual reconciliation have been exhausted. For in the Divine Law provision for divorce has been made only as an unavoidable necessity; otherwise Allah does not approve that the marriage relationship that has been established between a man and a woman should ever break. The Holy Prophet (upon whom be Allah's peace) has said "Allah has not made lawful anything more hateful in His sight than divorce." (Abu Daud). And: "Of all the things permitted by the Law, the most hateful in the sight of Allah is the divorce, (Abu Daud)
The second object was to complement this section of the family law of Islam by supplying answers to the questions that had remained after the revelation of the commandments in Surah Al-Baqarah. So, answers have been supplied to the following questions:What would be the waiting period of the women, marriage with whom has been consummated and who no longer menstruate, or those who have not yet menstruated, in case they are divorced? What would be the waiting period of the woman, who is pregnant, or the woman whose husband dies, if she is divorced?And what arrangements would be made for the maintenance and lodging of the different categories of divorced women, and for the fosterage of the child whose parents have separated on account of a divorce?
Source: Sayyid Abul Ala Maududi - Tafhim al-Qur'an - The Meaning of the Quran