Al-Kāfi

Hadith 406
fastingwudu
2ـ عَلِيُّ بْنُ إِبْرَاهِيمَ عَنْ أَبِيهِ عَنْ إِسْمَاعِيلَ بْنِ مَرَّارٍ عَنْ يُونُسَ عَنْ أَبِي جَمِيلَةَ عَنْ زَيْدٍ عَنْ أَبِي عَبْدِ الله (عَلَيْهِ السَّلاَم) فِي الصَّائِمِ يَتَمَضْمَضُ قَالَ لا يَبْلَعْ رِيقَهُ حَتَّى يَبْزُقَ ثَلاثَ مَرَّاتٍ.
2. Ali ibn Ibrahim has narrated from his father from ‘Isma‘il ibn Marrar from Yunus from abu Jamilah from Zayd who has said the following: “I once asked abu ‘Abd Allah (a.s.), about a man who rinses his mouth when he is fasting. He (the Imam) said, ‘He must not swallow his saliva before discharging it out of his mouth three times.’”
Source: Shaykh Muḥammad b. Yaʿqūb al-Kulaynī