purified together

2 Chronicles 29:34
However, since there were not enough priests to skin all the burnt offerings, their Levite brothers helped them until the work was finished and until the priests had been consecrated. For the Levites had been more diligent in consecrating themselves than the priests had been.

2 Chronicles 30:15-17
And on the fourteenth day of the second month they slaughtered the Passover lamb. The priests and Levites were ashamed, and they consecrated themselves and brought burnt offerings to the house of the LORD. . . .

killed

Exodus 12:21
Then Moses summoned all the elders of Israel and told them, "Go at once and select for yourselves a lamb for each family, and slaughter the Passover lamb.

2 Chronicles 35:11
And they slaughtered the Passover lambs, while the priests sprinkled the blood handed to them and the Levites skinned the animals.

Hebrews 7:27
Unlike the other high priests, He does not need to offer daily sacrifices, first for His own sins and then for the sins of the people; He sacrificed for sin once for all when He offered up Himself.