Sahih Muslim Book 54, Hadith 41
The Euphrates would soon uncover a mountain of gold but he who is present there should not take anything from that.
The Last Hour would not come unless the Euphrates would uncover a treasure of gold, so he who finds it should not take anything out of that.
I was standing along with Ubayy b. Ka`b and he said: The opinions of the people differ in regard to the achievement of worldly ends. I said: Yes, of course. Thereupon he said: I heard Allah's Messenger (ﷺ) as saying: The Euphrates would soon uncover a mountain of gold and when the people would bear of it they would flock towards it but the people who would possess that (treasure) (would say): If we allow these persons to take out of it they would take away the whole of it. So they would fight and ninety-nine out of one hundred would be killed. Abu Kamil in his narration said: I and Ubayy b. Ka`b stood under the shade of the battlement of Hassan.