Jamieson, Fausset and Brown on 2 Chronicles 32:31

31. in the business of the ambassadors who sent ... to inquire of the wonder that was done in the land, &c.--They brought a present (2Ch 32:23; see on 2Ki 20:12, 13), and a letter of congratulation on his recovery, in which particular enquiries were made about the miracle of the sun's retrocession--a natural phenomenon that could not fail to excite great interest and curiosity at Babylon, where astronomy was so much studied. At the same time, there is reason to believe that they proposed a defensive league against the Assyrians.

God left him, to try him, &c.--Hezekiah's offense was not so much in the display of his military stores and treasures, as in not giving to God the glory both of the miracle and of his recovery, and thus leading those heathen ambassadors to know Him.