Please provide an example of where Whitman compares death and life?

There is a theme of immortality that runs throughout "Song
of Myself" as the speaker discusses life and death as a cycle.  If you review Section 6,
you will see at the end where the speaker discusses the question of what happens to
people after death in relationship to life.

In talking
about the "dead young men and women" the speaker
says:

They
are alive and well somewhere,
The smallest sprout shows there is really no
death,
And if ever there was it led forward life, and does not wait at the

end to arrest it,
And ceas'd the moment life
appear'd.

All goes onward and outward, nothing collapses,

And to die is different from what any one supposed, and
luckier.

Remember that
Whitman was alive and wrote during the transitional time from romanticism (and
transcendentalism) to realism.  In a way, his assertions could be looked at as a view of
death from both a natural (and therefore romantic) standpoint as well as a
scientific/realistic standpoint.  If nothing else, he acknowledges that life and death
are part of the same cycle.  In comparing death to life, here, the speaker explains
death does not really exist because ultimately it leads to a rebirth of something else. 
This second chance is what the speaker means when he says death is "different" and
"luckier" than what most always considered it.