Is it sufficient to use fewer than three stones for Istijmar?
Chapter on Cleaning oneself (Istitabah) and Impurity (Hadath)
Al-Mughni
Book of Purification
Primary text
A narration from Ahmad states that it is not sufficient to use less than three stones for Istinja'. Abu Bakr ibn al-Mundhir affirms this view, citing the statement of the Prophet (peace be upon him): 'None of you should perform Istinja' with less than three stones,' and 'None of you should suffice with less than three stones.' The evidence provided is that if one uses a single stone for Istijmar, that stone becomes impure, making its reuse impermissible, analogous to small stones.
Supporting text
The primary scholarly position holds that if one performs Istijmar three times with a purifying material meeting all specified conditions, it suffices, just as if three small pieces were separated and used. There is no difference in the act of purification between the whole object and its separated parts. The Hadith implies three cleansing passes (wiping motions) with a stone, not necessitating three distinct stones, similar to saying 'he struck me three lashes' meaning three blows with one whip. This interpretation is supported by allowing wood, rags, baked earth, or even wiping a large rock or wall in three distinct spots, demonstrating that the meaning is derivable from the concept of three actions rather than the specific number of stones.