Hezekiah was a good king who did what was right in the eyes of the Lord (2 Kings 18:3-6). However, on some level, he was clueless and naive. When messengers from the king of Babylon came with gifts, Hezekiah showed them all the treasures of his palace and kingdom (20:13-15). Trusting these strangers was a foolish thing to do.

Furthermore, when Isaiah told him that all of the treasures and some of his own descendants would be carried off to Babylon, Hezekiah viewed this as a "good" thing, thinking that at least this meant that there would be peace in his own lifetime (2 Kings 20:17-19). So either he was incredibly naive or else just very self-centered.

Some have believed that when Hezekiah became ill and was at the point of death, and then God extended his life fifteen years (2 Kings 20:1-6), God did this because Hezekiah was such a righteous, faithful king. Yet, it also can be considered that God had His own agenda (as He always does). Had He not spared Hezekiah, Israel probably would have been taken captive by Assyria. But since it was God's plan for Israel to be taken captive by Babylon, He spared Hezekiah's life, who then showed all of Israel's treasures to messengers from Babylon, motivating Babylon to take the treasures and people back to Babylon.