Abu Hurairah narrates a hadith and that appears to be speaking about impertinence towards fatwas and lacking due diligence and care in issuing legal verdicts and accusations of disbelief, in addition to the ease of branding all opponents as being the inhabitants of the hell fire.  Abu Hurairah narrated that the Messenger of Allah (PBUH) said:

“In the end of time there shall come men who will swindle the world with religion, deceiving the people in soft skins of sheep, their tongues are sweeter than sugar and their hearts are the hearts of wolves. Allah [Mighty and Sublime is He] says: ‘Is it me you try to delude or is it against me whom you conspire? By Me, I swear to send upon these people, among them, a Fitnah that leaves them utterly devoid of reason.” Reported by Ibn Mubarak in Kitab al-Zuhd and al-Tirmidhi in his al-Sunan.