Thematic Bible: Irregularities in

But he told them, "Haven't you read what David did when he and his companions were hungry? How is it that he went into the house of God and ate the Bread of the Presence, which was not lawful for him and his companions to eat but was reserved for the priests?

The king, his princes, and the entire assembly in Jerusalem had mutually decided to observe the Passover in the second month, but they had been unable to celebrate it then because not enough priests had consecrated themselves and the people had not yet been gathered together in Jerusalem. This decision seemed to be a good one in the opinion of the king and of the entire assembly, read more.
so they published a decree that was circulated throughout Israel from Beer-sheba to Dan that they are to come celebrate the Passover to the LORD God of Israel in Jerusalem. The Passover had not been celebrated in great numbers as was being prescribed by the decree.

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. Even though a large crowd of people from as far away as Ephraim, Manasseh, Issachar, and Zebulun had not completed consecrating themselves, they still ate the Passover in a manner not proscribed by the Law, because Hezekiah had prayed like this for them: "May the good LORD extend a pardon on behalf of everyone who prepares his own heart to seek God, the LORD God of his ancestors, even though he does so inconsistent with the laws of consecration." read more.
The LORD listened to Hezekiah and healed the people.