C. F. Keil and Franz Delitzsch on 2 Chronicles 30:6

2Ch 30:6 “The runners (whether soldiers of the royal body-guard, cf. 2Ch 12:10, or other royal couriers, as Est 3:13, Est 3:15, cannot be determined) went with letters from the hand of the king, ... and according to the commandment of the king to say.” Tot he written invitation of the king and his princes they were to add words of exhortation: “Turn again to Jahve, ... that He may return (turn Himself) to the remnant which remains to you from the hand of the kings of Assyria,” i.e., of Tiglath-pileser and Shalmaneser.