How we cite our quotes: All quotations are from Seven.
Quote #1
["Greed" is written on the carpet in blood.]
When the attorney is discovered with his stomach cut open and the word "greed" written in blood on the carpet, the detectives know something is up. Even though the gluttony murder is discovered first, the name of the sin is hidden behind the fridge. Here, it's out in the open. The lawyer's sin is public. The fat man's sin is private.
Quote #2
"Long is the way, and hard, that out of Hell leads up to Light." (Paradise Lost)
This quote is on a note left for the detectives by the killer. Paradise Lost is about original sin, so it's appropriate that the killer leaves his note at the site of his first murder.
Quote #3
SOMERSET: There are seven deadly sins, captain. Gluttony, greed, sloth, wrath, pride, lust, and envy. Seven.
Everything so far has been a setup for this. This serves the purpose of letting us know the killer's religiously influenced motivation and adds suspense. Seven sins means seven murders, and knowing what to anticipate makes the movie more suspenseful, not less.