حَدَّثَنِي يَحْيَى، عَنْ زِيَادِ بْنِ عَبْدِ الرَّحْمَنِ، قَالَ حَدَّثَنَا مَالِكٌ، عَنْ سُمَىٍّ، مَوْلَى أَبِي بَكْرِ بْنِ عَبْدِ الرَّحْمَنِ أَنَّ أَبَا بَكْرِ بْنَ عَبْدِ الرَّحْمَنِ، اعْتَكَفَ فَكَانَ يَذْهَبُ لِحَاجَتِهِ تَحْتَ سَقِيفَةٍ فِي حُجْرَةٍ مُغْلَقَةٍ فِي دَارِ خَالِدِ بْنِ الْوَلِيدِ ثُمَّ لاَ يَرْجِعُ حَتَّى يَشْهَدَ الْعِيدَ مَعَ الْمُسْلِمِينَ ‏.

Yahya related to me that Ziyad ibn Abd ar-Rahman said, "Malikrelated to us from Sumayy, the mawla of Abu Bakr ibn Abd ar-Rahman,that Abu Bakr ibn Abd ar-Rahman was once doing itikaf and he would goout to relieve himself in a closed room under a roofed passage inKhalid ibn Walid's house. Otherwise he did not leave his place ofitikaf until he went to pray at the Id with the muslims." Translation Not Available

Book Ref: Muwatta Imam Malik Book 19 Hadith 697
Web Ref:  Muwatta Imam Malik Book 19 Hadith 5