Sunan an-Nasai Book 24, Hadith 2967

أَخْبَرَنَا مُحَمَّدُ بْنُ مَنْصُورٍ، قَالَ حَدَّثَنَا سُفْيَانُ، عَنِ الزُّهْرِيِّ، عَنْ عُرْوَةَ، قَالَ قَرَأْتُ عَلَى عَائِشَةَ ‏{‏ فَلاَ جُنَاحَ عَلَيْهِ أَنْ يَطَّوَّفَ بِهِمَا ‏}‏ قُلْتُ مَا أُبَالِي أَنْ لاَ أَطُوفَ بَيْنَهُمَا ‏.‏ فَقَالَتْ بِئْسَمَا قُلْتَ إِنَّمَا كَانَ نَاسٌ مِنْ أَهْلِ الْجَاهِلِيَّةِ لاَ يَطُوفُونَ بَيْنَهُمَا فَلَمَّا كَانَ الإِسْلاَمُ وَنَزَلَ الْقُرْآنُ ‏{‏ إِنَّ الصَّفَا وَالْمَرْوَةَ مِنْ شَعَائِرِ اللَّهِ ‏}‏ الآيَةَ فَطَافَ رَسُولُ اللَّهِ صلى الله عليه وسلم وَطُفْنَا مَعَهُ فَكَانَتْ سُنَّةً ‏.‏

It was narrated that Urwah said:"I recited to Aishah: 'So it is not a sin on him who performs Hajj or Umrah (Pilgrimage) of the House to Perform the going Tawaf) between them (as-Safa and Al-Marwah) "I said: 'I do not care if I do not go between tham?' She said: 'What a bad thing you have said!' People at the time of the Jahiliyyah used not to go between them, but when Islam came and the Quran was revealed: 'Verily, As-Safa and Al-Marwah are of the symols of Allah, the Messenger of Allah went between them, and we did that with him, and thus it became part of Hajj