Malachi 3:5

At that time the Lord assured His people that He would draw near to them, but it would be for judgment. He would quickly judge all types of sin that they practiced, whereas in Malachi’s day, and now, He waits to judge (cf. 2 Peter 3:9-10). The Levites would not be the only Jews He judged; all the Israelites living then would come under His judgment (cf. Ezekiel 20:34-38). He would judge them for all types of activity forbidden for His people: sorcery; adultery; lying; oppression of employees, widows, and orphans; mistreatment of aliens; even all forms of irreverence for Him. This was His answer to their claim that He was unjust (Malachi 2:17).