✅Answer: Study the following narrations:

✅Rinsing the mouth means circulating water in the mouth, and sniffing means drawing water into the nose. These are two practices from the Sunnah before wudu, before ghusl, and after using the toothbrush. However, for a fasting person, there are specific rulings as follows:

1 عَنْ حَمَّادٍ عَنْ أَبِي عَبْدِ اللَّهِ فِي الصَّائِمِ يَتَوَضَّأُ لِلصَّلَاةِ فَيَدْخُلُ الْمَاءُ حَلْقَهُ فَقَالَ إِنْ كَانَ وُضُوؤُهُ لِصَلَاةٍ فَرِيضَةٍ فَلَيْسَ عَلَيْهِ شَيْ ءٌ وَ إِنْ كَانَ وُضُوؤُهُ لِصَلَاةٍ نَافِلَةٍ فَعَلَيْهِ الْقَضَاءُ.

📚 Al-Kafi, vol.4, p.107

Imam al-Sadiq (peace be upon him) said regarding a fasting person performing wudu for prayer, if water accidentally enters his throat: If his wudu is for an obligatory prayer, there is no harm; if it is for a supererogatory prayer, he must make up that day of fasting.

2 عَنْ حَمَّادٍ عَمَّنْ ذَكَرَهُ عَنْ أَبِي عَبْدِ اللَّهِ فِي الصَّائِمِ يَتَمَضْمَضُ وَ يَسْتَنْشِقُ قَالَ نَعَمْ وَ لَكِنْ لَا يُبَالِغْ.

📚 Al-Kafi, vol.4, p.107

Imam al-Sadiq (peace be upon him) said regarding a fasting person who rinses and sniffs water: Yes (it is permissible), but he should not exaggerate or overdo it.

3 عَنْ يُونُسَ قَالَ: الصَّائِمُ فِي شَهْرِ رَمَضَانَ يَسْتَاكُ مَتَى شَاءَ وَ إِنْ تَمَضْمَضَ فِي وَقْتِ فَرِيضَةٍ فَدَخَلَ الْمَاءُ حَلْقَهُ فَلَيْسَ عَلَيْهِ شَيْ ءٌ وَ قَدْ تَمَّ صَوْمُهُ وَ إِنْ تَمَضْمَضَ فِي غَيْرِ وَقْتِ فَرِيضَةٍ فَدَخَلَ الْمَاءُ حَلْقَهُ فَعَلَيْهِ الْإِعَادَةُ وَ الْأَفْضَلُ لِلصَّائِمِ أَنْ لَا يَتَمَضْمَضَ.

📚 Al-Kafi, vol.4, p.107

Yunus said: (Imam peace be upon him said) A fasting person may brush his teeth whenever he wishes. If he rinses for an obligatory prayer and water enters his throat, there is no harm and his fast remains valid. If he rinses outside the obligatory prayer time and water enters his throat, he must make up the fast. It is better for a fasting person not to rinse.

4 عَنْ سَمَاعَةَ فِي حَدِيثٍ قَالَ: سَأَلْتُهُ عَنْ رَجُلٍ عَبِثَ بِالْمَاءِ يَتَمَضْمَضُ بِهِ مِنْ عَطَشٍ فَدَخَلَ حَلْقَهُ قَالَ عَلَيْهِ قَضَاؤُهُ وَ إِنْ كَانَ فِي وُضُوءٍ فَلَا بَأْسَ بِهِ.

📚 Al-Tahdhib, vol.4, p.322

Sama‘a said: I asked Imam al-Sadiq (peace be upon him) about someone who plays with water due to thirst and rinses, and water accidentally enters his throat. He said: He must make up the fast. If this happens during wudu for an obligatory prayer, there is no harm.

5 عَنْ زَيْدٍ الشَّحَّامِ عَنْ أَبِي عَبْدِ اللَّهِ فِي الصَّائِمِ يَتَمَضْمَضُ قَالَ لَا يَبْلَعْ رِيقَهُ حَتَّى يَبْزُقَ ثَلَاثَ مَرَّاتٍ.

📚 Al-Kafi, vol.4, p.107

Imam al-Sadiq (peace be upon him) said regarding a fasting person who rinses: He should not swallow the water until he has spit it out three times.

✅According to the above narrations, it is better for a fasting person not to rinse. However, permission is generally granted as mentioned in narration 2️⃣, with the recommendation not to overdo it. If rinsing is done for wudu of an obligatory prayer and water accidentally enters the throat, the fast remains valid and there is no problem. But if rinsing is for supererogatory prayer, for play, to remove bad breath, or generally for non-obligatory purposes, and water enters the throat accidentally, he must make up the fast, though the fast is still completed. Additionally, a person rinsing must spit out the water three times before swallowing. Sheikh Kulayni mentioned in continuation that "once" has also been narrated, but it is better and more cautious to follow the three-time practice as per the primary narration.

اللَّهُمَّ صَلِّ عَلَی مُحَمَّدٍ وَ آلِ مُحَمَّدٍ

وَ عَجِّلْ لِوَلِیِّکَ الْفَرَجَ وَ الْعَافِیَةَ وَ النَّصْرَ