They are at rest.
We may not stir the heav'n of their repose
By rude invoking voice, or prayer addrest
  In waywardness to those
Who in the mountain grots of Eden lie,
And hear the fourfold river as it murmurs by.

 ... 

  And soothing sounds
Blending with the neighb'ring waters as they glide;
Posted along the haunted garden's bounds,
  Angelic forms abide,
Echoing, as words of watch, o'er lawn and grove
The verses of that hymn which Seraphs chant above.