ومن لم يستطع منكم طولا أن ينكح المحصنات المؤمنات فمن ما ملكت (4:25) بالانجليزي

(4:25) And those of you who cannot afford to marry free, believing women (muhsanat), then marry such believing women whom your right hands possess. Allah knows all about your faith. All of you belong to one another. *45 Marry them, then, with the leave of their guardians, and give them their bridal-due in a fair manner that they may live in the protection of wedlock rather than be either mere objects of unfettered lust or given to secret love affairs. Then if they become guilty of immoral conduct after they have entered into wedlock, they shall be liable to half the penalty to which free women (muhsanat) are liable. *46 This relaxation is for those of you who fear to fall into sin by remaining unmarried. *47 But if you persevere, it is better for you. Allah is All-Forgiving, All-Compassionate.

Tafseer Abu-al-A'la Maududi

Page 82 English Traditional

*45). The difference between the status of people is relative. All Muslims are alike. If there is any true distinction its basis is a person's faith and faith is not an exclusive privilege of the rich or so-called upper classes of the society. So it is possible for a slave-girl to be superior, in respect of her faith and morals, to a woman belonging to the elite of a society.
*46).A superficial reading of this verse can lead to the mistaken conclusion, as Khawarij and others have done, that stoning is not the prescribed punishment for adultery. Such people ask: If stoning is the prescribed punishment for extra-marital sexual intercourse, then how is it possible to halve that punishment with regard to slave-girls? Such people have not noted carefully the wording of this verse. In this section (see verses 24-5) the term muhsanat (protected women) is used in two different meanings. First, it is used in the sense of 'married women', that is, those who enjoy the protection of their husbands. Second, it is used in the sense of 'women belonging to families', i.e. those who enjoy the protection of families even though they may not be married. In the verse under discussion, the word muhsanat is used in the latter sense, i.e. in the sense of women who enjoy the protection of families as opposed to slave-girls. At the same time, the word is also used in the first meaning, when slave-girls have acquired the protection accorded by the contract of marriage (fa idha uhsinna), they will be liable to the punishment laid down in this verse if they have unlawful Sexual intercourse.
It is therefore apparent that a free woman enjoys two kinds of protection. One is the protection of her family through which she remains protected even when she is not married. The second is the protection of her husband, which reinforces the protection of the family that she already enjoys. As long as the slave-girl remains a slave, she does not enjoy the protection of the family. However, when she is married she has the protection of her husband - and of her husband alone. This protection is partial. Even after marriage she is neither liberated from the bond of her master nor does she attain the status enjoyed by free women. The punishment prescribed for a married slave-girl is accordingly half the punishment of an unmarried free woman rather than half that of a married free woman.
This also explains that the punishment for unlawful sexual intercourse (zina) laid down in Surah al-Nur 24: 2 refers to the offence committed by unmarried free women alone, and it is in comparison with their punishment that the punishment of married slave women has been laid down as half. As for free married women, they deserve more severe punishment than the unmarried free women (muhsanat) for they violate the double protection. Even though the Qur'an does not specifically mention punishment by stoning it does allude to it in a subtle manner.
*47). That is, if a man cannot afford to marry a free woman then he should marry a slave-girl with the permission of her master.