Sayyiduna Ibn Abbas (may Allah be pleased with them both) said: I saw the Messenger of Allah (peace and blessings be upon him) in a dream at midday, dishevelled and covered with dust, and in his hand was a glass bottle containing blood. I said: O Messenger of Allah! May my father and mother be your ransom, 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." Then that day was reckoned, and it was found that he had been martyred on that very day.
Hadith Referenceالمعجم الكبير للطبراني / باب الحاء / 2809