Also, it appears that others were introducing controversial ideas. Even if the latter were not directly unscriptural, they were divisive.
فَكَانَ بَعْضُ أَعْضَاءِ ٱلْجَمَاعَةِ يُرَوِّجُونَ تَعَالِيمَ مُرْتَدَّةً .‏