The Power of the Dog ending explained

What happens

Peter deliberately lets Phil handle a diseased cattle hide. Phil's cut hand lets anthrax in, and he dies, written off as an accident. The ending reveals Peter's gentleness was cover for a plan to protect his mother.

The last image

Peter, safe at home, looks at the rope Phil braided him while a psalm about being delivered from the power of the dog plays in his mind.

What it says

Phil's performance of toughness hid a secret, and Peter, the boy he mocked, saw it clearly. The film ends on this reversal so you must reread everything: strength and weakness were never what they seemed, and quiet watching was a kind of power.