2 Chronicles 30:17

Because there were so many in the assembly that had not consecrated themselves, therefore the descendants of Levi supervised the slaughter of the Passover sacrifices on behalf of everyone who remained unclean, so they could be consecrated to the LORD.

2 Chronicles 29:34

Because there weren't enough priests, they were unable to prepare all the burnt offerings until other priests came forward after having consecrated themselves, so their descendant of Levi relatives assisted them until the services were complete. (The descendants of Levi had been more conscientious in consecrating themselves than had been the priests.)

Exodus 12:6

It is to remain under your care until the fourteenth day of this month, and then the entire assembly of the congregation of Israel is to slaughter it at twilight.

2 Chronicles 35:3-6

He addressed the descendants of Levi who were teaching all Israel and who had consecrated themselves to the LORD, telling them:

Treasury of Scripture Knowledge

Summary

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.

The levites

2 Chronicles 29:34

2 Chronicles 35:3

The killing

Exodus 12:6

Bible References

The levites

He addressed the descendants of Levi who were teaching all Israel and who had consecrated themselves to the LORD, telling them:

The killing

It is to remain under your care until the fourteenth day of this month, and then the entire assembly of the congregation of Israel is to slaughter it at twilight.