Musnad Ahmad 908:13

Isma'il narrated to us, Ayyub informed us, from Humayd ibn Hilal, from a man from 'Abd al-Qays who was with the Khawarij, then left them, he said: They entered a village, and 'Abd Allah ibn Khabbab came out, terrified, dragging his garment. They said: "Do not be afraid." He said: "By Allah, you have terrified me." They said: "Are you 'Abd Allah ibn Khabbab, the companion of the Messenger of Allah, may Allah bless him and grant him peace?" He said: "Yes." They said: "Did you hear from your father a hadith he narrated from the Messenger of Allah, may Allah bless him and grant him peace, that you can narrate to us?" He said: "Yes, I heard him narrating from the Messenger of Allah, may Allah bless him and grant him peace: that he mentioned a tribulation (fitna) in which the one sitting is better than the one standing, the one standing is better than the one walking, and the one walking is better than the one running." He said: "If you reach that, then be 'Abd Allah the killed." Ayyub said: "And I do not know him to have said anything but, 'And do not be 'Abd Allah the killer.'" They said: "Did you hear this from your father narrating it from the Messenger of Allah, may Allah bless him and grant him peace?" He said: "Yes." They said: "So they brought him forward to the bank of the river and struck his neck, and his blood flowed like the strap of a sandal, not scattering. And they ripped open his slave-mother (umm walad) for what was in her womb."