`Sayyiduna Anas (may Allah be pleased with him) says that when the Prophet Muhammad (peace and blessings be upon him) was taken up to the heavens (i.e., during the Mi'raj), he said: "I came to a river on whose banks were domed tents made of hollow pearls. I asked Jibreel (may Allah be pleased with him), 'What is this?' He replied, 'This is (your river) Kawthar.'"