✅Answer: Please pay attention to the following narrations:

1 عَنْ إِبْرَاهِيمَ بْنِ عَبْدِ الْحَمِيدِ عَنْ أَبِي الْحَسَنِ قَالَ: دَخَلَ رَسُولُ اللَّهِ عَلَى عَائِشَةَ- وَ قَدْ وَضَعَتْ قُمْقُمَتَهَا فِي الشَّمْسِ فَقَالَ يَا حُمَيْرَاءُ مَا هَذَا قَالَتْ أَغْسِلُ رَأْسِي وَ جَسَدِي قَالَ لَا تَعُودِي فَإِنَّهُ يُورِثُ الْبَرَصَ

📚 Al-Tahdhib, Vol. 1, p. 366

Imam Kadhim (peace be upon him) said: 'The Messenger of Allah (peace be upon him and his family) entered upon Aisha while she had placed her flask under the sun!'

The Prophet said: 'O Humaira! What is this?!' She said: 'I want to wash my head and body with it!'

The Prophet said: 'Do not do this again, for it causes baras (a skin disease like vitiligo)!'

2 عَنْ إِسْمَاعِيلَ بْنِ أَبِي زِيَادٍ عَنْ أَبِي عَبْدِ اللَّهِ قَالَ: قَالَ رَسُولُ اللَّهِ الْمَاءُ الَّذِي تُسَخِّنُهُ الشَّمْسُ لَا تَتَوَضَّئُوا بِهِ وَ لَا تَغْتَسِلُوا بِهِ وَ لَا تَعْجِنُوا بِهِ فَإِنَّهُ يُورِثُ الْبَرَصَ.

📚 Al-Kafi, Vol. 3, p. 15

Imam Sadiq (peace be upon him) said: 'The Messenger of Allah (peace be upon him and his family) said: 'Do not perform ablution with water that the sun has heated and made hot, and do not perform ghusl with it, and do not make dough with it, for it causes baras (a skin disease like vitiligo)!'

3 عَنْ مُحَمَّدِ بْنِ سِنَانٍ عَنْ بَعْضِ أَصْحَابِنَا عَنْ أَبِي عَبْدِ اللَّهِ قَالَ: لَا بَأْسَ بِأَنْ يَتَوَضَّأَ الْإِنْسَانُ بِالْمَاءِ الَّذِي يُوضَعُ فِي الشَّمْسِ.

📚 Al-Tahdhib, Vol. 1, p. 366

Imam Sadiq (peace be upon him) said: 'There is no problem for a person to perform ablution with water that has been placed in the sun!'

✅ It is clear from the above narrations that performing ablution and ghusl, making dough, and washing the head and body with water that has been heated and made hot by the sun causes the disease of baras and has been forbidden.

However, considering the permission (rukhsa) mentioned in narration 3, and with attention to the statement of Imam Reza (peace be upon him) in 📚 Uyun Akhbar al-Ridha (peace be upon him), Vol. 2, p. 20, Hadith 45, who said in a hadith:

فَمَا كَانَ عَنْ رَسُولِ اللَّهِ نَهْيَ إِعَافَةٍ أَوْ أَمْرَ فَضْلٍ فَذَلِكَ الَّذِي يَسَعُ اسْتِعْمَالُ الرُّخْصَةِ فِيهِ إِذَا وَرَدَ عَلَيْكُمْ عَنَّا الْخَبَرُ فِيهِ بِاتِّفَاقٍ يَرْوِيهِ مَنْ يَرْوِيهِ فِي النَّهْيِ وَ لَا يُنْكِرُهُ وَ كَانَ الْخَبَرَانِ صَحِيحَيْنِ مَعْرُوفَيْنِ بِاتِّفَاقِ النَّاقِلَةِ فِيهِمَا يَجِبُ الْأَخْذُ بِأَحَدِهِمَا أَوْ بِهِمَا جَمِيعاً أَوْ بِأَيِّهِمَا شِئْتَ وَ أَحْبَبْتَ مُوَسَّعٌ ذَلِكَ لَكَ مِنْ بَابِ التَّسْلِيمِ لِرَسُولِ اللَّهِ وَ الرَّدِّ إِلَيْهِ وَ إِلَيْنَا...

Permission has also been given to perform ablution with such water, but in light of the prohibition of the Ahl al-Bayt (peace be upon them) from this act and one of its negative consequences being the creation of the skin disease baras, it is appropriate to avoid using water heated by the sun in the aforementioned cases.

✅ What has been said about this prohibition being limited to a small amount of water or to water inside a container has no narrative basis, and the absolute nature of the above narrations prevents it.

✅ The cooling down of the water after being heated by the sun does not remove the prohibition from it, because it has been absolutely forbidden to perform ghusl, ablution, make dough, and wash the head and body with water that has been heated and made hot by the sun, and the removal of its undesirability after cooling requires a specific statement from the Ahl al-Bayt (peace be upon them), which does not exist.

اللَّهُمَّ فَصَلِّ عَلَی مُحَمَّدٍ وَ آلِ مُحَمَّدٍ وَ عَجِّلْ لِوَلِیِّکَ الْفَرَجَ وَ الْعَافِیَةَ وَ النَّصْرَ

﷽Peace be upon you and the mercy of Allah and His blessings

A collection of special supplications for the advent [of the Mahdi] which has been compiled by one of the believers.

God willing, may you benefit from it and spread it among the believers, in the hope of the nearing advent of the remnant of Allah, peace be upon him.

اللَّهُمَّ فَصَلِّ عَلَی مُحَمَّدٍ وَ آلِ مُحَمَّدٍ وَ عَجِّلْ لِوَلِیِّکَ الْفَرَجَ وَ الْعَافِیَةَ وَ النَّصْرَ