Prohibition on Eating Blood
Where this fits in the story: Genesis 9:4 — very strong pre-Sinai root: flesh with its life/blood must not be eaten.
Where Scripture takes it next: Acts 15:20,29 — strong verbal/canonical correspondence but disputed derivation. Gentile believers are told to abstain from blood; Leviticus 17 is a major Torah background because its commands repeatedly include the resident alien.