"The good beginning made at the time of the purification of the temple was followed by a broader movement, in which Israel as well as Judah participated. In his zeal to make the temple services a real blessing to the people, Hezekiah determined to revive the ancient custom of gathering the Israelites together for the celebration of the Passover feast. PK 335.3"
"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."
Both passages directly refer to Hezekiah's initiative to revive the Passover celebration and invite Israelites from both Judah and Israel to participate. The EGW passage elaborates on Hezekiah's motivations and the broader context of the revival.
"For many years the Passover had not been observed as a national festival. The division of the kingdom after the close of Solomon's reign had made this seem impracticable. But the terrible judgments befalling the ten tribes were awakening in the hearts of some a desire for better things; and the stirring messages of the prophets were having their effect. By royal couriers the invitation to the Passover at Jerusalem was heralded far and wide, “from city to city through the country of Ephraim and Manasseh even unto Zebulun.” The bearers of the gracious invitation were usually repulsed. The impenitent turned lightly aside; nevertheless some, eager to seek God for a clearer knowledge of His will, “humbled themselves, and came to Jerusalem.” 2 Chronicles 30:10, 11 . PK 335.4"
"So the posts passed from city to city through the country of Ephraim and Manasseh even unto Zebulun: but they laughed them to scorn, and mocked them."
EGW directly quotes and references 2 Chronicles 30:10, making it a clear explicit allusion.