From Ibn Kathir's "Signs of the Day of Judgment":

Abd Allah ibn Umar said: "The Prophet (SAW) came to us and said, 'O Muhajirun (Emigrants from Makkah to Madinah) you may be afflicted by five things, God forbid that you should live to see them. If fornication should become widespread, you should realize that this has never happened without new diseases befalling the people which their forebears never suffered. If people should begin to cheat when weighing out goods, you should realize that this has never happened without drought and famine befalling the people, and their rulers oppressing them. If people should withhold Zakat, you should realize that this has never happened without the rain being stopped from falling; and were it not for the animal's sake, it would never rain again. If people should break their covenant with Allah and His Messenger, you should realize that this has never happened without Allah sending an enemy against them to take some of their possessions by force. If the leaders do not govern according to the book of Allah, you should realize that this has never happened without Allah making them into groups and making them fight one another.' " (Ibn Majah)