Sayyinduna Amr Bin Auf Al Ansaari RA relates that Rasullulah SAWW sent Sayyiduna Abu Ubaidah bin Al Jarrah RA to Behrain to collect tax. The Ansaar on hearing about his return with tax, assembled around Nabi SAWW at the time of Fajr Salaah. Upon completing Salaah, Nabi SAWW smiled upon them as he saw them gathered there, He then remarked, "i think you people have received news that Abu Ubaidah has returned from Bahrain with something". The companions replied, "yes, O Rasulullah SAWW"
He said "I give you glad tidings and you should entertain hopes about what would please you. By ALLAH i do not fear poverty upon you, (rather) I fear that the material world will be opened for you as it was opened for those before you. Then you will incline towards for material wealth just like the people before you. (The love of) this material wealth will be the cause of your destruction just as it was for the people before you."
(Bukhari, Muslim, as narrated in Targheeb and Hayaatus Sahabah)