וַיֵּלְכוּ֩ הָרָצִ֨ים בָּֽאִגְּר֜וֹת מִיַּ֧ד הַמֶּ֣לֶךְ וְשָׂרָ֗יו בְּכָל־יִשְׂרָאֵל֙ וִֽיהוּדָ֔ה וּכְמִצְוַ֥ת הַמֶּ֖לֶךְ לֵאמֹ֑ר בְּנֵ֣י יִשְׂרָאֵ֗ל שׁ֚וּבוּ אֶל־יְהוָ֗ה אֱלֹהֵי֙ אַבְרָהָם֙ יִצְחָ֣ק וְיִשְׂרָאֵ֔ל וְיָשֹׁב֙ אֶל־הַפְּלֵיטָ֔ה הַנִּשְׁאֶ֣רֶת לָכֶ֔ם מִכַּ֖ף מַלְכֵ֥י אַשּֽׁוּר׃
So the posts went with the letters from the king and his princes throughout all Israel and Judah, and according to the commandment of the king, saying: ‘Ye children of Israel, turn back unto the LORD, the God of Abraham, Isaac, and Israel, that He may return to the remnant that are escaped of you out of the hand of the kings of Assyria.
Rashi
and therein shall the poor of His people shelter themselves Even from the ten tribes they would come there, as is related in II Chron. (30:6), “Hezekiah sent messengers throughout the border of Israel, to return to the Holy One, blessed be He.