Al-Kāfi - Volume 4 > Minimum Limits of ’1‘tikaf
Hadith #3

3ـ أَحْمَدُ بْنُ مُحَمَّدٍ عَنِ ابْنِ مَحْبُوبٍ عَنْ أَبِي أَيُّوبَ عَنْ مُحَمَّدِ بْنِ مُسْلِمٍ عَنْ أَبِي جَعْفَرٍ (عَلَيْهِ السَّلاَم) قَالَ إِذَا اعْتَكَفَ يَوْماً وَلَمْ يَكُنِ اشْتَرَطَ فَلَهُ أَنْ يَخْرُجَ وَيَفْسَخَ الاعْتِكَافَ وَإِنْ أَقَامَ يَوْمَيْنِ وَلَمْ يَكُنِ اشْتَرَطَ فَلَيْسَ لَهُ أَنْ يَفْسَخَ اعْتِكَافَهُ حَتَّى يَمْضِيَ ثَلاثَةُ أَيَّامٍ.

3. Ahmad ibn Muhammad from has narrated from ibn Mahbub from abu Ayyub from Muhammad ibn Muslim who has said the following: “Abu Ja‘far, ‘Alayhi al-Salam, has said, ‘If one remains in Ttikaf for one day without setting a condition, he can leave and depart the ’ Ttikaf but if one remains in ’Ttikaf for two days without condition being set, he then cannot leave out the ’Ttikaf; until three days are complete.’”