What did the Prophet Muhammad (peace be upon him) say when 'Umar and 'Ammar were in a military detachment and had a seminal emission but no water to take a bath?
 Abd al-Rabmin b. Abza narrated It on the authority of his father that a man came to 'Umar and said:                      I am (at times) affected by seminal emission but find no water. He ('Umar) told him not to say prayer. 'Ammar then said. Do you remember,0 Commander of the Faithful, when I and you were in a military detachment and we had had a seminal emission and did not find water (for taking bath) and you did not say prayer, but as for myself I rolled in dust and said prayer, and (when it was mentioned before) the Apostle (may peace be upon him) said: It was enough for you to strike the ground with your hands and then blow (the dust) and then wipe your face and palms. Umar said: 'Ammar, fear Allah. He said: If you so like, I would not narrate it. A hadith like this has been transmitted with the same chain of transmitters but for the words: 'Umar said: We hold you responsible for what you claim."