https://en.wikipedia.org/wiki/The_Pledge_(film)
(There’s two DVD rips listed by the indexer I use but neither of them is the complete film, and no streaming service has it.)
https://www.netflix.com/gb/title/60004419
I found it using this:
https://www.justwatch.com/uk/search?q=The%20Pledge&content_t...
(This appears to be a recent change by Netflix where they list movies that can’t actually be viewed. Another example of a movie listed by Netflix but not viewable there is the documentary “The Wrecking Crew” - https://www.netflix.com/title/70105364)
This movie really doesn’t seem to be legally streamable. I found a supposed Bluray rip of it via TPB, and an HN reader emailed me links to a couple very poor quality DVD rips on various sketchy web sites, and there’s some even worse quality CD sized rips on Usenet. The physical media is no longer for sale, and I’m not sure it was ever released to BR, the torrent I found (and still transferring) notwithstanding.
(I know, I know, it's one of their least 'significant' movies -- but IMO it's their most fun and watchable one).