כָּל־לְבָב֣וֹ הֵכִ֔ין לִדְר֛וֹשׁ הָאֱלֹהִ֥ים ׀ יְהוָ֖ה אֱלֹהֵ֣י אֲבוֹתָ֑יו וְלֹ֖א כְּטָהֳרַ֥ת הַקֹּֽדֶשׁ׃ (ס)
every one that setteth his heart to seek God, the LORD, the God of his fathers, though [he be] not [cleansed] according to the purification that pertaineth to holy things.’
Ramban
For he set his whole heart [to seek G-d],125See II Chronicles 30:19.
Rashi
over that which God had prepared for the people to serve Him and to do His will, similar to below (30:19): “His whole heart he set to seek, etc.,” and they also rejoiced because they were suddenly inspired in the first year of his reign to return to the Lord, and they returned immediately.