Albert Barnes Commentary 2 Chronicles 31:4

"Moreover he commanded the people that dwelt in Jerusalem to give the portion of the priests and the Levites, that they might give themselves to the law of Jehovah." — 2 Chronicles 31:4 (ASV)

That they might be encouraged... that is, to devote themselves wholly to their proper work: the service of the sanctuary and the teaching of God’s Law (2 Chronicles 17:7–9), and not engage in secular occupations .