2 Chronicles 30:1-2

Hezekiah sent word to all Israel and to Judah and also wrote letters to Ephraim and Manasseh to come to the house of the LORD at Jerusalem to celebrate the Passover Feast to the LORD God of Israel. For the king and his officials and all the assembly in Jerusalem had decided to celebrate the Passover in the second month, [Num 9:10, 11]