Hadith on the grief of Holy Prophet (s.a.w.a.) on witnessing the martyrdom of Imam Husain (a.s.).

Narrated Salma: “I entered upon Umm Salamah while she was crying, so said: “What causes you to cry?’ She said: ‘I saw the Messenger of Allah (s.a.w.a.) – that is, in a dream – and there was dirt on his head and his beard. So I said: “What is wrong with you, o Messenger of Allah (s.a.w.a.)?” He said: ‘I just witnessed the killing of Al-Husain (a.s.).'”
(Jamiat Tirmidhi English : Vol. 1, Book 46, Hadith 3771, Arabic: Book 49, Hadith 4140)