Sahih Muslim Book 003, Hadith Number 0718.
Chapter : Tayammum.
Abd al-Rahmin 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, O 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."