The Black Stones of Iona

Here on their knees men swore; the stones were black,
Black in the people's minds and words, yet they
Were at that time, as now, in colour grey.
But what is colour, if upon the rack
Of conscience souls are placed by deeds that lack
Concord with oaths? What differ night and day
Then, when before the Perjured on his way
Hell opens, and the heavens in vengeance crack
Above his head uplifted in vain prayer
To Saint, or Fiend, or to the Godhead whom
He had insulted--Peasant, King, or Thane?
Fly where the culprit may, guilt meets a doom;
And, from invisible worlds at need laid bare,
Come links for social order's awful chain.