Crape ... Lawn
A saint in crape is twice a saint in lawn. (Pope: Ep. to Cobham, 136.) Crape (a sort of bombazine, or alpaca) is the stuff of which cheap clerical gowns used to be made, and here means one of the lower clergy; “lawn” refers to the lawn sleeves of a bishop, and here means a prelate. A good curate is all very well, but the same goodness in a bishop is exalted as something noteworthy.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894