Clean and Unclean Land Animals
Where this fits in the story: Genesis 7:1–10 — very strong pre-Sinai background. Noah already distinguishes clean and unclean animals before Leviticus gives Israel a detailed food/purity system.
Where Scripture takes it next: Mark 7:1–23 is central to later Christian interpretation of food purity; many translations understand Mark 7:19 as “declaring all foods clean,” while the Greek syntax/scope remains debated.
Evidence boundary: Dietary categories are not simply “healthy versus unhealthy,” and neither Mark 7 nor Acts 10 should be summarized in a way that hides genuine interpretive questions.