Where in the book is situational irony used?

From the text:

"You regard it as impossible that a sinner should be struck down by the wrath of God! I do not!"

The judge stroked his chin. He murmured in a slightly ironic voice:  "My dear lady, in my experience of ill-doing, Providence leaves the work of conviction and chastisement to us mortals-and the process is often fraught with difficulties."