Hadith 517950
Chapter 56: Speech - كتاب الكلام
وَحَدَّثَنِي مَالِكٌ، عَنْ سُهَيْلِ بْنِ أَبِي صَالِحٍ، عَنْ أَبِيهِ، عَنْ أَبِي هُرَيْرَةَ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ " إِذَا سَمِعْتَ الرَّجُلَ يَقُولُ هَلَكَ النَّاسُ . فَهُوَ أَهْلَكُهُمْ " .
Malik related to me from Suhayl ibn Abu Salih from his father from Abu Hurayra that the Messenger of Allah, may Allah bless him and grant him peace, said, "When you hear a man say, 'The people are ruined,' he himself is the most ruined of them all."
Reference Muwatta Malik 517950
USC-MSA web (English) reference : Book 56, Hadith 2