Fatwa: Cleansing hidden impurities
--answered by Sayyid Allama Muhammad bin Abdul-Azeem al-Houthi
One is to act upon assumption. By that I mean that one is to clean it until one assumes that the impurity is removed--even if it was just twice. By these washings, one has acted in accordance with what is established in At-Tahreer. This is closest to the explicit text of al-Hadi and al-Qasim. The [washing] three times is not explicitly mentioned except in the Prophetic narrations. The later scholars use this as a proof because of the explicit Prophetic statement. However, al-Hadi explicitly mentions it in Al-Ahkaam but does not state that it is to be done three times. He only mentions that the ritual impurity is to be removed and one is to be certain of it. Similar is stated in Al-Muntakhab [another book by al-Hadi] and likewise is mention by al-Qasim bin Ibrahim (as). The apparent denotation of the proof is that the ritual impurity is to be removed and purified, that is by removing it.
The hadith of washing three times is authentic and it is among the reports from al-Hadi as was mentioned; however, the apparent denotation is specific to the hand that one desires to dip into the water.