Matthew Poole and continuators on 2 Chronicles 30:1

1 ANd Hezekiah sent to all Israel and Judah, and wrote letters also to Ephraim and Manasseh , that they should come to the house of the LORD at Jerusalem , to keep the passover unto the LORD God of Israel.

Whereby he understands all the Persons of the Ten Tribes, who were now setled in his Kingdom; as appears by their contradistinction to Ephraim and Manasseh here following.

i. e. To all the remainders of the Ten Tribes, v. 5. who are here Synecdochically expressed by the names of Ephraim and Manasseh, as elsewhere by the name of Ephraim onely. But he names these two Tribes, because they were nearest to his Kingdom, and a great Number of them had long since and from time to time joyned themselves to the Kingdom of Judah, 2 Chron. 15. 8, 9. and therefore had most hopes of success amongst them.

Admonishing them of their Duty to God and perswading them to comply with it.