What is the ruling regarding one who performs Tayammum, begins prayer, and then sees water without using it before completing the prayer?
Chapter on Tayammum
Al-Mughni
Book of Purification
Primary text
If it is ruled that seeing water invalidates the prayer that was commenced based on tayammum, then the prayer is nullified. The ability to use water nullifies the tayammum, requiring the person to perform a new tayammum and offer a fresh prayer.
Supporting text
If it is ruled that seeing the water does not invalidate the ongoing prayer, then according to Ibn Aqil and the position of Al-Shafi'i, the person is prohibited from using that tayammum to begin another prayer because seeing the water invalidates the allowance for initiating a new prayer based on that tayammum.