Musnad Abu Ya'la al-Mawsili 155:81

Abu Sa'id al-Ashajj narrated to us, Abu Usamah narrated to us, he said: Muhammad ibn 'Amr narrated to me, from Abu Salamah, from Abu Hurayrah, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "Four rivers flowed from Paradise: the Euphrates, the Nile—the Nile of Egypt—Sayhan, and Jayhan."