Al-Qasim bin Abd al-Rahman said: A complaint was made to Abdullah bin Mas'ud (may Allah be pleased with him) about the Euphrates (river). People said: "We fear that it will burst over us; if only you would send someone to it who would build an embankment for it." Abdullah (may Allah be pleased with him) said: "We will not build an embankment for it. By Allah, a time will come upon people when, if they were to search for even a basin of water, they would not find it. Every water will return to its original source, and the water will be where the Muslims are, in al-Sham."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 8824