'Passover lambs' in the Bible

Then on the fourteenth day of the second month they put the Passover lambs to death: and the priests and the Levites were shamed, and made themselves holy and took burned offerings into the house of the Lord.

For there were still a number of the people there who had not made themselves holy: so the Levites had to put Passover lambs to death for those who were not clean, to make them holy to the Lord.

And they put the Passover lambs to death, the blood being drained out by the priests when it was given to them, and the Levites did the skinning.