Zaynab bint Jahsh (may Allah be pleased with her) reported that the Prophet (may Allah's peace and blessings be upon him) came to her in an alarmed state, saying: "There is no god but Allah. Woe to the Arabs from an impending evil. Today, an aperture has been made in the wall of Gog and Magog, like this," making a circle with his thumb and index fingers. So I said: "O Messenger of Allah, shall we perish while there are pious people among us?" He said: "Yes, when wickedness is rampant." [Sahih/Authentic] - [Al-Bukhari and Muslim]

عن زينب بنت جحش -رضي الله عنها- أنَّ النبي -صلى الله عليه وسلم- دخل عليها فَزِعًا، يقول: «لا إله إلا الله، وَيْلٌ لِلْعَرَبِ مِنْ شَرٍّ قد اقْتَرَب، فُتِحَ اليوم من رَدْمِ يَأْجُوجَ ومَأجُوجَ مثل هذه»، وحلَّق بأُصبُعيه الإبهامِ والتي تَلِيها، فقلت: يا رسول الله، أنَهْلِكُ وفينا الصَّالِحُون؟ قال: «نعم، إِذَا كَثُرَ الخَبَثُ». [صحيح.] - [متفق عليه.]