They slaughtered the Passover lambs on the fourteenth of the second month. The priests and Levites were ashamed of themselves. They consecrated themselves and brought burnt offerings to the house of Jehovah. They stood in their regular places as instructed by the law of Moses. Moses was a man of God. The priests sprinkled the blood they received from the Levites. Many people in the assembly had not made themselves holy. So the Levites had to kill the Passover lambs for all who were not clean and could not make their lambs holy for Jehovah. read more.
Many people from Ephraim, Manasseh, Issachar, and Zebulun had not made themselves clean. So they ate the Passover, but not in the way the written instructions said they should. Hezekiah prayed for them: May Jehovah forgive everyone who have their hearts set on dedicating their lives to serve God. May Jehovah the God of their ancestors do this for those who are not clean as required for the holy place.

It was the Jewish Passover. Many went out of the country to Jerusalem to purify themselves before the Passover. Verse ConceptsPassoverPurifying OneselfNear The Time Generally