2 Chronicles 30:17
For there were many in the congregation that were not sanctified: therefore the Levites had the charge of the killing of the passovers for every one that was not clean, to sanctify them unto the Lord.
Cross-references
2 Chronicles 29:34 records Levites helping slaughter offerings because priests were too few — the same pattern of Levites stepping in.
In 2 Chronicles 35:3-6, Josiah directs Levites to slaughter Passover lambs for the people — identical role as here.
In Ezekiel 44:11, Levites are assigned to slay sacrifices for the people — the exact same role they perform here for the Passover lambs.
In John 11:55, many Jews purified themselves before Passover — reflecting the same need for ritual cleanliness that required Levite intervention here.
Exodus 12:6 has each household slaughter the lamb, whereas here Levites do it for the unclean — a contrast in who performs the act.
Numbers 9:7 shows men unclean from a corpse asking about Passover — a parallel situation of impurity affecting Passover participation.