(regarding His Statement): 'They ask your instruction concerning the women. Say: Allah instructs you about them ...' (4.127) It is about the female orphan who is under the guardianship of a man with whom she shares her property and he does not want to marry her and dislikes that someone else should marry her, lest he should share the property with him, so he prevents her from marrying. So Allah forbade such a guardian to do so (i.e. to prevent her from marrying).  

عَنْ عَائِشَةَ ؓ فِي قَوْلِهِ {وَيَسْتَفْتُونَكَ فِي النِّسَاءِ قُلِ اللَّهُ يُفْتِيكُمْ فِيهِنَّ} إِلَى آخِرِ الآيَةِ قَالَتْ هِيَ الْيَتِيمَةُ تَكُونُ فِي حَجْرِ الرَّجُلِ قَدْ شَرِكَتْهُ فِي مَالِهِ فَيَرْغَبُ عَنْهَا أَنْ يَتَزَوَّجَهَا وَيَكْرَهُ أَنْ يُزَوِّجَهَا غَيْرَهُ فَيَدْخُلَ عَلَيْهِ فِي مَالِهِ فَيَحْبِسُهَا فَنَهَاهُمُ اللَّهُ عَنْ ذَلِكَ  

While we were sitting in the company of the Prophet ﷺ a woman came to him and presented herself (for marriage) to him. The Prophet ﷺ looked at her, lowering his eyes and raising them, but did not give a reply. One of his companions said, "Marry her to me O Messenger of Allah ﷺ!" The Prophet ﷺ asked (him), "Have you got anything?" He said, "I have got nothing." The Prophet ﷺ said, "Not even an iron ring?" He Saʿd, "Not even an iron ring, but I will tear my garment into two halves and give her one half and keep the other half." The Prophet; said, "No. Do you know some of the Qur'an (by heart)?" He said, "Yes." The Prophet ﷺ said, "Go, I have agreed to marry her to you with what you know of the Qur'an (as her Mahr)."  

حَدَّثَنَا سَهْلُ بْنُ سَعْدٍ كُنَّا عِنْدَ النَّبِيِّ ﷺ جُلُوسًا فَجَاءَتْهُ امْرَأَةٌ تَعْرِضُ نَفْسَهَا عَلَيْهِ فَخَفَّضَ فِيهَا النَّظَرَ وَرَفَعَهُ فَلَمْ يُرِدْهَا فَقَالَ رَجُلٌ مِنْ أَصْحَابِهِ زَوِّجْنِيهَا يَا رَسُولَ اللَّهِ قَالَ أَعِنْدَكَ مِنْ شَىْءٍ قَالَ مَا عِنْدِي مِنْ شَىْءٍ قَالَ وَلاَ خَاتَمًا مِنْ حَدِيدٍ قَالَ وَلاَ خَاتَمًا مِنَ حَدِيدٍ وَلَكِنْ أَشُقُّ بُرْدَتِي هَذِهِ فَأُعْطِيهَا النِّصْفَ وَآخُذُ النِّصْفَ قَالَ لاَ هَلْ مَعَكَ مِنَ الْقُرْآنِ شَىْءٌ قَالَ نَعَمْ قَالَ اذْهَبْ فَقَدْ زَوَّجْتُكَهَا بِمَا مَعَكَ مِنَ الْقُرْآنِ