Childe Harold analysis

Question

Could someone help me interpret these two parts of the poem because I got some idea of it but I'm not sure.

	My task is done, my song hath cease, my theme
	Has died into an echo; it is fit
30	The spell should break of this protracted dream.
	The torch shall be extinguished with hath lit
	My midnight lamp – and what is writ, is writ;
	Would it were worthier! but I am not now
	That which I have been – and my visions flit
35	Less palpably before me – and the glow
	Which in my spirit dwelt is fluttering, fain, and low.

5

	Farewell! a word that must e, and hath been –
	A sound which makes us linger; – yet – farewell!
	Ye! who have traced the Pilgrim to the scene
40	Which is his last, if in your memories dwell
	A thought which once was his, if on ye swell
	A single recollection, not in vain
	He wore his sandal shoon and scallop shell;
	Farewell! with him alone may rest the pain,
45	If such there were – with you, the moral of his strain.