Does this passage in King Lear develop the theme of compassion or truth?

This is from Act 5 Scene 3 of King Lear:

A plague upon you, murderers, traitors all!
I might have saved her. Now she’s gone for ever.—
Cordelia, Cordelia, stay a little. Ha?
What is ’t thou say’st?—Her voice was ever soft,
Gentle and low, an excellent thing in woman.—
I killed the slave that was a-hanging thee.

Do you think this would develop the theme of compassion or truth?
(I would also like to know whether the structure is prose, blank verse or rhyming iambic pentameter, since I have trouble identifying these. However, that may require a separate question.)