Chapter on Etiquettes of Causes Requiring Purification

Muhammad bin Ahmad bin Yahya narrated from Muhammad bin Al-Husayn, from Muhammad bin Khalid, from Abdullah bin Bukayr, who said: I said to Abu Abdullah عليه السلام: 'A man urinates but does not have water with him, so he wipes his private part on a wall.' Imam عليه السلام said: 'Everything dry and pure (tahir) is permissible.'