A few months ago the following passage from the Aisha Bewleys translation of the al-Shifa of Qadi Iyad made me think: If making a comparison between the physical features and beard of Rasul'ullah and the physical features and beard of an individual considered to be ugly is kufr. Then why is making a comparison between the knowledge of Rasul'ullah and the knowledge of "children, lunatics and animals" not?