فمحمول على من لم يستنج بالماء وإن كان قد استنجى بالاحجار أو لم يستنج بالاحجار وان كان قد استنجى بالماء فاما متى ذكر انه لم يستنج اصلا وجب عليه اعادة الصلاة والذي يدل على ذلك ما رواه
So this is to be understood as referring to the one who did not perform ‘istinjaʾ’ with water but had performed it with stones, or did not perform it with stones but had performed it with water. However, if he remembers that he did not perform ‘istinjaʾ’ at all, then it becomes obligatory upon him to repeat the prayer. What indicates this is what was narrated:
