Verse 58: ‘As for’ those who believe and go good, We will certainly house them in ‘elevated’ mansions in Paradise, under which rivers flow, to stay there forever. How excellent is the reward for those who work ‘righteously!’
Water has this aspect, when you see it flowing, like rivers or streams, it gives you coolness in the heart. Some narrations 
say that it is even good for the eyes. In this way, Allah (swt) is 
describing us things that make us happy. We will only achieve all this, if we follow Allah’s commandments on this earth. This is a kind of motivation or an incentive. It is not the goal.