عَنْ أُمِّ سَلَمَةَ رَضِيَ اللَّهُ عَنْهَا قَالَتْ لَمَّا قَدِمَ الْمُهَاجِرُونَ الْمَدِينَةَ عَلَى الْأَنْصَارِ تَزَوَّجُوا مِنْ نِسَائِهِمْ وَكَانَ الْمُهَاجِرُونَ يُجِبُّونَ وَكَانَتِ الْأَنْصَارُ لَا تُجَبِّي فَأَرَادَ رَجُلٌ مِنَ الْمُهَاجِرِينَ امْرَأَتَهُ عَلَى ذَلِكَ فَأَبَتْ عَلَيْهِ حَتَّى تَسْأَلَ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ قَالَتْ فَأَتَتْهُ فَاسْتَحْيَتْ أَنْ تَسْأَلَهُ فَسَأَلَتْهُ أُمُّ سَلَمَةُ فَنَزَلَتْ نِسَاؤُكُمْ حَرْثٌ لَكُمْ فَأْتُوا حَرْثَكُمْ أَنَّى شِئْتُمْ [سورة البقرة: ٢٢٣] وَقَالَ لَا إِلَّا فِي صِمَامٍ وَاحِدٍ
Lady Umm Salamah (may Allah be pleased with her) narrates that when the emigrants came to Madinah, they married women from among the Ansar. Now, the issue arose that the emigrant husbands would have intercourse with their wives while they were lying on their backs, whereas the Ansar did not do so. When one emigrant wanted to have intercourse with his wife in this manner, she refused and said: "I will not allow this until I ask the Prophet Muhammad (peace and blessings be upon him)." So she came, but she was too shy to ask about this issue. Lady Umm Salamah (may Allah be pleased with her) inquired about it from the Prophet (peace and blessings be upon him), and then this verse was revealed: {نِسَاؤُکُمْ حَرْثٌ لَّکُمْ فَاْتُوْا حَرْثَکُمْ اَنّٰی شِئْتُمْ} (Surah Al-Baqarah: 223) ... "Your wives are your fields; so come to your fields as you wish." Then the Prophet (peace and blessings be upon him) said: "Do not have intercourse except in one place (which is for intercourse)."