Musnad Abu Ya'la al-Mawsili 41:1

Khalaf ibn Hisham al-Bazzar narrated to us, Abu al-Ahwas narrated to us, from Mansur, from Hilal ibn Yasaf, from Sa'id ibn Zayd, who said: We were sitting with the Messenger of Allah (may Allah bless him and grant him peace), and he mentioned a tribulation and magnified it. He said: So we said, or they said, "O Messenger of Allah, if we live to see this, we will surely perish." He said: The Messenger of Allah (may Allah bless him and grant him peace) said: "Nay, it is sufficient for you [to face] killing." Sa'id said: I saw my brothers killed after that.