He lashed his horse quite unnecessarily as he galloped off.

He rode home at an outrageous rate.
And he was not, Solomon gives me to understand, in the habit of maltreating horses.
"Now what do you make of all this?
Here is a young man with an unexpended lot of temper on his hands--bent on being reckless; bent on being just as bad as he can be.

It's as clear as daylight.

That boy never committed any crime.

A man who had just murdered his father would not be filled with anger, no matter what the provocation had been.