Shaikh-ul-Islam Ibn Taymiyyah commented on this verse: "All who contradict and oppose the Messenger after the right path has been clearly shown to them, have followed other than the Path of the Believers; and all who follow other than the Path of the Believers have contradicted and opposed the Messenger after the right Path has been shown to them. If one thinks that he is following the Path of the Faithful Believers and is mistaken, he is in the same position as one who thinks he is following the Messenger and is mistaken."
Biography of the noble scholar, Shaikh-ul-Islam Ibn Taymiyyah: http://fatwa-online.com/scholarsbiographies/8thcentury/ibntaymiyyah.htm
