Musnad Ahmad 5:654

Yazid narrated to us, Hisham informed us, from Muhammad, from Ubaydah, from Ali, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said on the day of the Trench: "What is the matter with them? May Allah fill their houses and their graves with fire, just as they detained us from the middle prayer until the sun set."