Who can forget the image at the end of the film of the Bible with the perfectly cut-out space for Andy's rock hammer? The Bible does double duty in the film, too, playing on two different takes on the word "salvation." The warden tells Andy to read the Bible, telling him that "salvation lies within." Of course, by salvation, the religious hypocrite warden means salvation of the soul through Christ, which Bible-reading presumably leads to. For Andy, salvation does lie within that Bible, but in a literal way—it's where he's hid his means of escape, safely out of reach of the inspections. The warden gets clued in on that in one of those "deeply satisfying" scenes at the end of the movie.
Profoundly philosophical as we are, it all makes Shmoop think of the real meaning of salvation. The warden's version is shallow and generic: Read some Bible verses and you're good to go, regardless of how you actually behave. The difficult path, Andy's version, is to save yourself, by persevering, hanging on to what you can of your integrity, and keeping those little flickers of hope burning in the face of degradation and despair. We are so deep.