Chapter on the Recommended Fasts of the Year
Man Lā Yaḥḍuruh al-Faqīh|Volume 2|Book 2|Chapter 4
وَ رَوَى اَلْفُضَيْلُ بْنُ يَسَارٍ عَنْ أَبِي عَبْدِ اَللَّهِ عَلَيْهِ اَلسَّلاَمُ قَالَ: «إِذَا صَامَ أَحَدُكُمُ اَلثَّلاَثَةَ اَلْأَيَّامَ مِنَ اَلشَّهْرِ فَلاَ يُجَادِلَنَّ أَحَداً وَ لاَ يَجْهَلْ وَ لاَ يُسْرِعْ إِلَى اَلْحَلْفِ وَ اَلْأَيْمَانِ بِاللَّهِ فَإِنْ جَهِلَ عَلَيْهِ أَحَدٌ فَلْيَحْتَمِلْ ».
It is narrated by al-Fudhayl ibn Yasar from Abu Abdullah (Imam Jafar ibn Muhammad Al-Sadiq عليه السلام) who said: "When one of you fasts the three days of the month, let him not dispute with anyone, act ignorantly, or hasten to take oaths by Allah سبحانه وتعالى. If someone acts ignorantly toward him, let him endure it."
- Ṣaḥīḥ al-Faqīh, p. 90