Musannaf Ibn Abi Shayba 37:519

Yazid ibn Harun narrated to us, he said: Ibn 'Awn informed us, from Umayr ibn Ishaq, he said: I heard Abu Hurayrah saying: "Woe to the Arabs from an evil that has drawn near. By Allah, it has loomed; it is swifter toward them than a lean, fast horse. The deafening tribulation, the ambiguous one; a man wakes up in it upon one affair and goes to sleep upon another. The one sitting in it is better than the one standing, and the one standing in it is better than the one walking, and the one walking in it is better than the one running. And if I were to tell you everything that I know, you would cut my throat from here"—and he took the back of his neck with the edge of his palm. "O Allah, do not let the rule of the boys reach Abu Hurayrah." And he raised his hands until he made their backs toward the palm of his hand.