Al-Kāfi - Volume 4 > ‘1‘tikaf is not Valid without Fasting
Hadith #1

1ـ عِدَّةٌ مِنْ أَصْحَابِنَا عَنْ سَهْلِ بْنِ زِيَادٍ عَنْ أَحْمَدَ بْنِ مُحَمَّدٍ عَنْ دَاوُدَ بْنِ الْحُصَيْنِ عَنْ أَبِي الْعَبَّاسِ عَنْ أَبِي عَبْدِ الله (عَلَيْهِ السَّلاَم) قَالَ لا اعْتِكَافَ إِلاَّ بِصَوْمٍ.

1. A number of our people have narrated from Sahl ibn Ziyad from Ahmad ibn Muhammad from Dawud ibn al-Huseen from abu al-‘Abbas who has said the following: “Abu ‘Abd Allah, ‘Alayhi al-Salam, has said, ‘Without fast ’I‘tikaf is not valid.’”