Al Bara’ (bin Azib) said “When a man fasted and slept, he could not eat till (another nigh) like it.” Sarmah bin Qais Al Ansari came to his wife while he was fasting and asked her Do you have something (to eat)? She replied “No”. Let me go and seek something for you. So, she went out and sleep overcame him. She came (back) and said (to him) .You are deprived (of food). He fainted before noon. He used to work all day long at his land. This was mentioned to the Prophet ﷺ. So the following verse was revealed. “Permitted to you on the nights of the fasts, is the approach to your wives. They are your garments and ye are their garments. Allah knoweth what yes used to do secretly amongst yourselves. But he turned to you and forgave you. So now associate with them and seek what Allaah hath ordained for you. And eat and drink until the white thread of dawn appears to you. He recited up to the words “of dawn”.  

لاَ لَعَلِّي أَذْهَبُ فَأَطْلُبُ لَكَ شَيْئًا فَذَهَبَتْ وَغَلَبَتْهُ عَيْنُهُ فَجَاءَتْ فَقَالَتْ خَيْبَةً لَكَ فَلَمْ يَنْتَصِفِ النَّهَارُ حَتَّى غُشِيَ عَلَيْهِ وَكَانَ يَعْمَلُ يَوْمَهُ فِي أَرْضِهِ فَذَكَرَ ذَلِكَ لِلنَّبِيِّ ﷺ فَنَزَلَتْ { أُحِلَّ لَكُمْ لَيْلَةَ الصِّيَامِ الرَّفَثُ إِلَى نِسَائِكُمْ } قَرَأَ إِلَى قَوْلِهِ { مِنَ الْفَجْرِ }