Oxus, Jaxartes, Euphrates, and the Nile are all from the rivers of Paradise
Authentic hadithعن أبي هريرة رضي الله عنه قال: قال رسول الله صلى الله عليه وسلم : « سَيْحَانُ وَجَيْحَانُ وَالفُرَاتُ والنِّيل كلٌّ من أنهار الجنة».
Abu Hurayrah (may Allah be pleased with him) reported that the Messenger of Allah (may Allah's peace and blessings be upon him) said: "Oxus, Jaxartes, Euphrates, and the Nile are all from the rivers of Paradise."
Explanation
The Oxus, the Jaxartes, the Euphrates, and the Nile are four rivers in this world, which the Prophet (may Allah's peace and blessings be upon him) described as being from the rivers of Paradise. Some scholars said that they are literally from the rivers of Paradise. However, when these rivers were put in this world, they earned the character of worldly rivers and became from the rivers of this world.
Source · Narrated by Muslim
From the Hadith Encyclopedia (hadeethenc.com).