Analysis of In San Lorenzo

Is thine hour come to wake, O slumbering Night?
  Hath not the Dawn a message in thine ear?
  Though thou be stone and sleep, yet shalt thou hear
When the word falls from heaven--Let there be light.
Thou knowest we would not do thee the despite
  To wake thee while the old sorrow and shame were near;
  We spake not loud for thy sake, and for fear
Lest thou shouldst lose the rest that was thy right,
The blessing given thee that was thine alone,
The happiness to sleep and to be stone:
  Nay, we kept silence of thee for thy sake
Albeit we knew thee alive, and left with thee
The great good gift to feel not nor to see;
  But will not yet thine Angel bid thee wake?