Translation:

19. He has let free the two bodies of flowing water meeting together:

Notes (Tafseer)

5185. See xxv. 53, and n. 3111, where it is explained how the two bodies of water, salt and sweet, meet together, yet keep separate, as if there was a barrier or partition between them. This is also one of the favours of Allah. Sea-water is a sanitating agent, while fresh water is sweet and palatable to drink.