And who are these, like shadows thin,
Heaving vast hammers without din,
Splitting in fragments huge the ledge;
Noiseless, with crowbar and with wedge,
In silence plying chisel's edge!

They bear the marks of steel and fire;
Upon each brow the impress dire
Of sin, and shame, and penalty,
As driven from the upper sky,
And doomed in God's rebuke to sigh.