What are two literary devices and their lines used in Dante's Inferno Canto 20?

When
Dante feels pity for the souls he meets in20 (their heads have been twisted backwards so that
they are forever looking at where they have been, and never at where they are going), Virgil
rebukes him with:

"Here pity most doth show herself
alive, / When she is dead." (lines 26-27)

There are
two techniques within this quotation. The first is the("herself ... she") of pity, and
the second is the seemingof "most ... alive, / When she is dead." It doesn't at first
appear to make much sense that pity can be most alive when dead. In the original Italian version
of the text, however, the word was not "pity" but "pieta," which has a
double meaning, meaning both pity and piety. So, with this in mind, we can deduce that perhaps
Virgil is saying that the pity that lives in Dante has no place with these damned souls because
they have proven themselves impious. With this interpretation, we can...