Sunan At-Tirmidhi

Narrated Salma:""I entered upon Umm Salamah while she was crying, so I said: 'What causes you to cry?' She said: 'I saw the Messenger of Allah - that is, in a dream - and there was was dirt on his head and his beard. so I said: ""What is wrong with you, O Messenger of Allah?"" He said: 'I just witnessed the killing of Al-Husain