وَهَـذَا مِلْحٌ أُجَاجٌ
(and that is salty and bitter;) meaning that it is salty, bitter and not easy to swallow. This is like the seas that are known in the east and the west, the Atlantic Ocean and the Straits that lead to it, the Red Sea, the Arabian Sea, the Persian Gulf, the China Sea, the Indian Ocean, the Mediterranean Sea, the Black Sea and so on, all the seas that are stable and do not flow, but they swell and surge in the winter and when the winds are strong, and they have tides that ebb and flow. At the beginning of each month the tides ebb and flood, and when the month starts to wane they retreat until they go back to where they started. When the crescent of the following month appears, the tide begins to ebb again until the fourteenth of the month, then it decreases. Allah, may He be glorified, the One Whose power is absolute, has set these laws in motion, so all of these seas are stationary, and He has made their water salty lest the air turn putrid because of them and the whole earth turn rotten as a result, and lest the earth spoil because of the animals dying on it. Because its water is salty, its air is healthy and its dead are good (to eat), hence when the Messenger of Allah was asked whether sea water can be used for Wudu', he said: