It is narrated from Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) that he said: I saw the Prophet (peace and blessings be upon him) in a dream at midday, his hair dishevelled and covered in dust, with a flask containing blood. I said: O Prophet of Allah, what is this? He (peace and blessings be upon him) said: "This is the blood of Husayn and his companions; I have been gathering it continuously since today." The narrator said: That day was calculated, and it was found that Sayyiduna Husayn (may Allah be pleased with him) had been martyred one day before that. This hadith is sahih (authentic) on the condition of Imam Muslim, but the two Shaykhs (Bukhari and Muslim) did not record it.