Jamieson, Fausset and Brown on 2 Kings 20:12-19

12-19. Berodach-baladan--(Is 39:1), the first king of Babylon mentioned in sacred history; formerly its rulers were viceroys of the Assyrian monarchs. This individual threw off the yoke, and asserting his independence, made with varying success, a long and obstinate resistance [Rawlinson, Outlines]. The message of congratulation to Hezekiah, was, in all likelihood, accompanied with proposals for a defensive alliance against their common Assyrian enemy. The king of Judah, flattered with this honor, showed the ambassadors all his treasures, his armory and warlike stores; and his motive for this was evidently that the Babylonian deputies might be the more induced to prize his friendship.