He sighed heavily.
"This is a judgment upon me," he said presently.

He turned his great eyes full upon Justin, and their dance was infinitely wistful.

"Do you remember, Justin, that night at your lodging--that first night on which we talked here in London of the thing you were come to do--the thing to which I urged you?
Do you recall how you upbraided me for having set you a task that was unworthy and revolting ?" "I remember," answered Justin, with an inward shudder, fearful of what might follow.
"Oh, you were right, Justin; right, and I was entirely wrong--wickedly wrong.

I should have left vengeance to God.

He is wreaking it.
Ostermore's whole life has been a punishment; his end will be a punishment.