1
general::
Ignorant or inexperienced individuals get involved in situations that wiser persons would avoid, as in I've never heard this symphony and here I am conducting it? oh well, fools rush in where angels fear to tread, or He tried to mediate their unending argument? fools rush in. This expression, so well known it is sometimes shortened as in the second example, is a quotation from Alexander Pope's Essay on Criticism (1709): "No place so sacred from such fops is barr'd . . . Nay, fly to altars; there they'll talk you dead; For fools rush in where angels fear to tread."
American Heritage Idioms
2
general::
Phrase(s): Fools rush in where angels fear to tread.
Prov. Foolish people usually do not understand when a situation is dangerous, so they are not afraid to do things that would frighten more sensible people. • Alan: Bob is too scared to go in and confront the boss, so I’m going to. Jane: Fools rush in where angels fear to tread.
McGrawhill's American Idioms And Phrasal Verbs