Grocott & Ward, comps. Grocott’s Familiar Quotations, 6th ed. 189-?.

Vile

None become at once completely vile.
Juvenal.—Sat. 2. (Ramage 238.)

Crime like virtue, has its degrees.
Racine.—Phædrus, IV., 2. (Ramage 265.)

There is no man suddenly either excellently good, or extremely evil.
Sidney.—The Arcadia, Book I.

There is a method in man’s wickedness,
It grows up by degrees.
Beaumont and Fletcher.—A King and no King. Act V. Scene 4.