2 Chronicles 30:17

For [there were] many in the assembly who did not consecrate themselves, so the Levites [were] over the killing of the Passover sacrifices for all who [were] not clean, to consecrate [them] to Yahweh.

2 Chronicles 29:34

But the priests were too few, and they were not able to offer all the burnt offerings, so their brothers, the Levites, strengthened them to finish the work, and until the [rest of] the priests consecrated themselves. (For the Levites [were] {more conscientious} to sanctify themselves than the priests.)

Exodus 12:6

"{You will keep it} until the fourteenth day of this month, and all the assembly of the community of Israel will slaughter it {at twilight}.

2 Chronicles 35:3-6

And he said to the Levites who [were] teaching all Israel, who were sanctified to Yahweh, "Put the holy ark in the house which Solomon the son of David, king of Israel, built. There is no [need] to carry it on [your] shoulders. Now serve Yahweh your God and his people Israel.

Treasury of Scripture Knowledge

Summary

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 killing

Bible References

The levites

2 Chronicles 29:34
But the priests were too few, and they were not able to offer all the burnt offerings, so their brothers, the Levites, strengthened them to finish the work, and until the [rest of] the priests consecrated themselves. (For the Levites [were] {more conscientious} to sanctify themselves than the priests.)
2 Chronicles 35:3
And he said to the Levites who [were] teaching all Israel, who were sanctified to Yahweh, "Put the holy ark in the house which Solomon the son of David, king of Israel, built. There is no [need] to carry it on [your] shoulders. Now serve Yahweh your God and his people Israel.

The killing

Exodus 12:6
"{You will keep it} until the fourteenth day of this month, and all the assembly of the community of Israel will slaughter it {at twilight}.