The raven once in snowy plumes was drest,
White as the whitest dove's unsullied breast,
Fair as the guardian of the Capitol,
Soft as the swan; a large and lovely fowl
His tongue, his prating tongue had changed him quite
To sooty blackness from the purest white.
Cunning leads to knavery. It is but a step from one to the other, and that very slippery. Only lying makes the difference; add that to cunning, and it is knavery.