The Amount of Water for Ablution and Ghusl
Man Lā Yaḥḍuruh al-Faqīh|Volume 1|Book 1|Chapter 8
وَ سُئِلَ أَبُو اَلْحَسَنِ اَلرِّضَا عَلَيْهِ اَلسَّلاَمُ: عَنْ رَجُلٍ اِحْتَاجَ إِلَى اَلْوُضُوءِ لِلصَّلاَةِ وَ لَمْ يَقْدِرْ عَلَى اَلْمَاءِ فَوَجَدَ مَاءً بِقَدْرِ مَا يَتَوَضَّأُ بِهِ بِمِائَةِ دِرْهَمٍ هَلْ يَجِبُ عَلَيْهِ أَنْ يَشْتَرِيَهُ وَ يَتَوَضَّأَ بِهِ أَوْ يَتَيَمَّمَ فَقَالَ «بَلْ يَشْتَرِي قَدْ أَصَابَنِي مِثْلُ ذَلِكَ فَاشْتَرَيْتُ وَ تَوَضَّأْتُ وَ مَا يَسُوؤُنِي بِذَلِكَ مَالٌ كَثِيرٌ.
Abu Al-Hasan Imam Ali ibn Musa Ar-Ridha عليه السلام was asked about a man who needed to perform wudu for prayer but could not find water, except for a quantity of water worth a hundred dirhams. Should he buy it to perform wudu or should he perform tayammum (dry ablution)? Imam عليه السلام said: ""Rather, he should buy it. I have experienced a similar situation, and I bought it and performed wudu and I would not mind having that money”.
- Ṣaḥīḥ al-Faqīh