He named the two vast and abundant waters: the two seas. And the Euphrates: the one that is notably sweet until it reaches the point of sweetness. The bitter water is its opposite. And their merging: it means that they are adjacent and touching each other. It is by His power that He separates between them and prevents them from mixing. This is from His great ability. In the words of some: and the two seas: one of them with the other is merged, and the sweet water from them is mixed with the bitter. [The phrase 'mixed' might mean 'not mixed', so it should be clarified.] It is a barrier preventing mixing by His power, as His saying is: 'without visible pillars' means without visible pillars, which is His power. And it was read: salty, in the form of a verb. It was said that it is as if 'salty' was omitted for ease, as it was said: 'and a cold breeze', meaning 'cold'. If you say: 'and a stone that is forbidden', what does it mean? I say: it is the word that the one seeking refuge says, and we have explained it. Here it is used metaphorically, as if each of the two seas seeks refuge from the other and says to it: 'a forbidden stone', as it was said: 'let not one of them transgress against the other by mixing'. The absence of transgression there is like seeking refuge here: each one is made to appear as a transgressor against the other, so he seeks refuge from him. It is one of the finest metaphors and most evident of eloquence.