حَدَّثَنِي يَحْيَى ، عَنْ مَالِك ، أَنَّهُ بَلَغَهُ ، أَنَّ الْقَاسِمَ بْنَ مُحَمَّدٍ ، وَنَافِعًا مَوْلَى عَبْدِ اللَّهِ بْنِ عُمَرَ ، قَالَا : " لَا اعْتِكَافَ إِلَّا بِصِيَامٍ ، بِقَوْلِ اللَّهِ تَبَارَكَ وَتَعَالَى فِي كِتَابِهِ : وَكُلُوا وَاشْرَبُوا حَتَّى يَتَبَيَّنَ لَكُمُ الْخَيْطُ الأَبْيَضُ مِنَ الْخَيْطِ الأَسْوَدِ مِنَ الْفَجْرِ ثُمَّ أَتِمُّوا الصِّيَامَ إِلَى اللَّيْلِ وَلا تُبَاشِرُوهُنَّ وَأَنْتُمْ عَاكِفُونَ فِي الْمَسَاجِدِ سورة البقرة آية 187 ، فَإِنَّمَا ذَكَرَ اللَّهُ الْاعْتِكَافَ مَعَ الصِّيَامِ "
It reached Imam Malik (may Allah have mercy on him) that Hazrat Qasim bin Muhammad and Nafi', the freed slave of Sayyiduna Abdullah bin Umar (may Allah be pleased with them both), both used to say that i'tikaf is not valid without fasting, because Allah, Glorified and Exalted, has said in His Book: "Eat and drink until the white thread becomes distinct to you from the black thread of dawn. Then complete the fasts till the night, and do not approach your women while you are in i'tikaf in the mosques." So Allah, Glorified and Exalted, mentioned i'tikaf along with fasting.