Abdullah ibn Maslamah ibn Qa'nab narrated to us, Hammad ibn Salamah narrated to us, from Suhayl ibn Abi Salih, from his father, from Abu Hurayrah, who said: The Messenger of Allah, peace and blessings be upon him, said... And Yahya ibn Yahya narrated to us, he said: I read to Malik, from Suhayl ibn Abi Salih, from his father, from Abu Hurayrah, that the Messenger of Allah, peace and blessings be upon him, said: "If a man says: 'The people are ruined,' then he is the most ruined of them." Abu Ishaq said: I do not know whether it is 'the most ruined of them' with nasb (accusative) or 'the most ruined of them' with raf' (nominative).
Hadith Referenceصحيح مسلم / كتاب البر والصلة والآداب / 2623
Narrated Abu Hurairah: The Prophet ﷺ said: When you hear. . . . (Musa's version has): When a man says people have perished, he is the one who has suffered that fate most. Abu Dawud said: Malik said: If he says that out of sadness for the decadence of religion which he sees among the people, I do not think there is any harm in that. If he says that out of self-conceit and servility of the people, it is an abominable act which has been prohibited.
Shaykh Umar Farooq Saeedi
Benefits and Issues: Undoubtedly, no matter how righteous a person may be on his own, if he falls into the trap of self-admiration and arrogance due to satanic deception, then he is the one most likely to fall into destruction, as has been mentioned in the previous hadith 4901. Therefore, one should always avoid speaking boastful and evil words.
Source: Sunan Abu Dawood – Commentary by Shaykh Umar Farooq Saeedi, Page: 4983