I would not enter on my list of friends (Though graced with polish'd manners and fine sense, Yet wanting sensibility) the man Who needlessly sets foot upon a worm.
William Cowper
Friendship
A quote by William Cowper
From the source
The Task. Book vi. Winter Walk at Noon. Line 560.
Recorded in John Bartlett’s Familiar Quotations, ninth edition, 1905 printing.