Priests, Death Impurity, Mourning, Marriage, and Household Holiness
Where this fits in the story: Leviticus 10's mourning restrictions after Nadab/Abihu form a strong narrative/priestly background.
Where Scripture takes it next: Hebrews contrasts Aaronic priesthood with Christ's superior priesthood at the order/mediation level, but does not individually interpret priestly mourning or marriage rules.