I enjoyed reading the original essay, in which this phrase was used; from the English poet Alexander Pope's, "An essay on criticism", 1709:

Such shameless Bards we have; and yet 'tis true,
There are as mad, abandon'd Criticks too.
The Bookful Blockhead, ignorantly read,
With Loads of Learned Lumber in his Head,
With his own Tongue still edifies his Ears,
And always List'ning to Himself appears.
All Books he reads, and all he reads assails,
From Dryden's Fables down to Durfey's Tales.
With him, most Authors steal their Works, or buy;
Garth did not write his own Dispensary.
Name a new Play, and he's the Poet's Friend,
Nay show'd his Faults - but when wou'd Poets mend?
No Place so Sacred from such Fops is barr'd,
Nor is Paul's Church more safe than Paul's Church-yard:
Nay, fly to Altars; there they'll talk you dead;
For Fools rush in where Angels fear to tread.

: to the article: "Fools rush in where angels fear to
: tread"