Musannaf Ibn Abi Shayba 33:173

Ahmad ibn Ishaq narrated to us, from Wuhayb, he said: Abdullah ibn Tawus narrated to us, from his father, from Abu Hurayrah, he said: The Messenger of Allah (may Allah bless him and grant him peace) said: "People will be gathered in three ways: hopeful and fearful, and two upon a camel, and three upon a camel."