Chapter on I'tikaf (spiritual Retreat)
Man Lā Yaḥḍuruh al-Faqīh|Volume 2|Book 2|Chapter 38
وَ رَوَى أَبُو أَيُّوبَ عَنْ مُحَمَّدِ بْنِ مُسْلِمٍ عَنْ أَبِي جَعْفَرٍ عَلَيْهِ اَلسَّلاَمُ قَالَ: «إِذَا اِعْتَكَفَ اَلرَّجُلُ يَوْماً وَ لَمْ يَكُنِ اِشْتَرَطَ فَلَهُ أَنْ يَخْرُجَ وَ أَنْ يَفْسَخَ اِعْتِكَافَهُ وَ إِنْ أَقَامَ يَوْمَيْنِ وَ لَمْ يَكُنِ اِشْتَرَطَ فَلَيْسَ لَهُ أَنْ يَفْسَخَ اِعْتِكَافَهُ حَتَّى تَمْضِيَ ثَلاَثَةُ أَيَّامٍ ».
It is narrated by Abu Ayyub, from Muhammad ibn Muslim, from Abu Ja'far عليه السلام, who said: "If a man begins i'tikaf for one day and has not made any stipulation, he is allowed to leave and break his i'tikaf. However, if he has completed two days without making a stipulation, he is not permitted to break his i'tikaf until three days have been completed."
- Ṣaḥīḥ al-Faqīh, p. 112