Sonnet LXIV (64)

When I have seen by Time's fell hand defaced
The rich proud cost of outworn buried age;
When sometime lofty towers I see down-razed
And brass eternal slave to mortal rage;
When I have seen the hungry ocean gain
Advantage on the kingdom of the shore,
And the firm soil win of the watery main,
Increasing store with loss and loss with store;
When I have seen such interchange of state,
Or state itself confounded to decay;
Ruin hath taught me thus to ruminate,
That Time will come and take my love away.
This thought is as a death, which cannot choose
But weep to have that which it fears to lose.

2. The sumptuous buildings or other appurtenances of a generation or a people which has decayed and passed away, and which is now buried in the dust. 

4. Mortal rage. Deadly, destroying. "Mortal rage" refers to the supreme principle of Mutability and Decay. 

5-8. The words of K. Hen. IV., Part II., Act III. sc. i, lines 45-51, have been justly compared:

"O God, that one might read the book of fate,
And see the revolution of the times
Make mountains level, and the continent,
Weary of solid firmness, melt itself
Into the sea! and other times, to see
The beachy girdle of the ocean
Too wide for Neptune's hips," &c.

The following lines from Tennyson's In Memoriam, written, probably, to some extent, under Shakespearean influence, may also be given:

"There rolls the deep where grew the tree,
O earth, what changes hast thou seen!
There where the long street roars hath been
The stillness of the central sea.

The hills are shadows, and they flow
From form to form, and nothing stands;
They melt like mist, the solid lands,
Like clouds they shape themselves and go."

8. Extending its own domain by what the other loses, and losing by what the other gains. 

10. State. Magnificence, though in the previous line "state" seems to mean "condition." 

13. This thought is as a death. Causing anticipatively the pang of separation.