وَ رَوَى عَبْدُ اَللَّهِ بْنُ اَلْمُغِيرَةِ عَنْ حَبِيبٍ اَلْخَثْعَمِيِّ قَالَ: قُلْتُ لِأَبِي عَبْدِ اَللَّهِ عَلَيْهِ اَلسَّلاَمُ أَخْبِرْنِي عَنِ اَلتَّطَوُّعِ وَ عَنْ هَذِهِ اَلثَّلاَثَةِ اَلْأَيَّامِ إِذَا أَجْنَبْتُ مِنْ أَوَّلِ اَللَّيْلِ فَأَعْلَمُ أَنِّي قَدْ أَجْنَبْتُ فَأَنَامُ مُتَعَمِّداً حَتَّى يَنْفَجِرَ اَلْفَجْرُ أَصُومُ أَوْ لاَ أَصُومُ قَالَ «صُمْ ».
It is narrated by Abdullah ibn al-Mughira from Habib al-Khath'ami, who said: "I said to Abu Abdullah (Imam Jafar ibn Muhammad Al-Sadiq (a.s)): 'Inform me about optional fasting and about fasting on these three days. If I become in a state of janabah (major ritual impurity) at the beginning of the night and I know that I am in such a state but I deliberately sleep until dawn breaks, should I fast or not?' Imam (a.s) said: 'Fast.'"