Riyad as-Salihin

Ka'b bin 'Iyad (May Allah be pleased with him) reported: Messenger of Allah (ﷺ) said, "Verily, there is a Fitnah (trial) for every nation and the trial for my nation (or Ummah) is wealth."

[At- Tirmidhi, who classified it as Hadith Hasan Sahih].