Musnad Ahmed: Hadith 2161

I saw the Prophet (ﷺ) slept in the middle of the day;( he appeared) dishevelled and dusty, and he had with him a bottle in which there was blood that he was picking up or something that he was putting in it. I said: O Messenger of Allah, what is this? He said: “The blood of al-Husain and his companions; I have been collecting it all day.” ‘Ammar said: We remembered that day, and we found out that he had been killed on that day.