The Book of Menstruation (Kitab Al-Haid)
Muslim :: Book 3 : Hadith 719
'Abd al-Rahman b. Abza mnated it on the authority of his father that a man came to Umar and said: I have had a seminal emission but I found no water, and the rest of the hadith is the same but with this addition: 'Amr said: 0 Commander of the Faithful, because of the right given to you by Allah over me, if you desire, I would not narrate this hadith to anyone.