Messenger of Allah ﷺ said, "Soon the river "Euphrates" will disclose the treasure (the mountain) of gold, so whoever will be present at that time should not take anything of it." Al-A'raj narrated from Abii Huraira that the Prophet ﷺ said the same but he said, "It (Euphrates) will uncover a mountain of gold (under it).  

رَسُولُ اللَّهِ ﷺ يُوشِكُ الْفُرَاتُ أَنْ يَحْسِرَ عَنْ كَنْزٍ مِنْ ذَهَبٍ فَمَنْ حَضَرَهُ فَلاَ يَأْخُذْ مِنْهُ شَيْئًا قَالَ عُقْبَةُ وَحَدَّثَنَا عُبَيْدُ اللَّهِ حَدَّثَنَا أَبُو الزِّنَادِ عَنِ الأَعْرَجِ عَنْ أَبِي هُرَيْرَةَ عَنِ النَّبِيِّ ﷺ مِثْلَهُ إِلاَّ أَنَّهُ قَالَ يَحْسِرُ عَنْ جَبَلٍ مِنْ ذَهَبٍ