مُوَطَّأُ مَالِكٍ
Muwatta Malik 809
Hajj
وَحَدَّثَنِي عَنْ مَالِكٍ، عَنْ هِشَامِ بْنِ عُرْوَةَ، عَنْ أَبِيهِ، أَنَّ عَائِشَةَ أُمَّ الْمُؤْمِنِينَ، قَالَتْ مَا أُبَالِي أَصَلَّيْتُ فِي الْحِجْرِ أَمْ فِي الْبَيْتِ .
Yahya related to me from Malik from Hisham ibn Urwa from his father that A'isha, umm al-muminin, said, "I do not mind whether I pray in the Hijr or in the House." (i.e. praying in the Hijr is the same as praying in the House).
Arabic/English book reference: Book 20, Hadith 106