"There was nothing that Hezekiah did not show them."So he showed the envoys from Babylon everything? I think he didn't. He did not show them the LORD God of Israel! Why had they come? News had reached them about Hezekiah being healed, but even more than that, they had seen the great sign that had accompanied the healing. The writer of Chronicles emphasizes that they wanted to know more about what had happened: "...envoys were sent by the rulers of Babylon to ask him about the miraculous sign that had occurred in the land..."
2 Kings 20:13
(2 Chr. 32:31)
Let that sink in for a few moments.
The king of Babylon saw the sun do this amazing Backup Thing in the sky. This was unprecedented. He wanted to know what happened and why. He started by asking his wise men, then his vassal kings and rulers. They all said, "Yeah, we saw it, but we don't know what happened." Finally reports came in from the Kingdom of Judah that their God had given the sign to their king. So the Babylonian king sent envoys to find out more about this sign and the God behind the sign.
They showed up—probably with royal gifts—and Hezekiah was tickled pink that these Important People™ were all here to see him. Thus he showed them around the palace and the city, trying to impress them with how impressive he, King of Judah, really was.
Let me repeat: Babylon wanted to know about God but Hezekiah talked about gold. Babylon wanted to understand the Sign but Hezekiah showed off his signet rings. Babylon wanted to hear more Words about who this God was that could command the sun like that, but Hezekiah told them more about this World.
Hezekiah gave them Stuff® when only one thing was needful!
Why? Out of the heart the mouth speaks (Lk. 6:45) and he was storing up treasures on this earth so his heart was there with his treasures (Mt. 6:19-21).
This explains why he was so sad when Isaiah told him it was time to die. He was attached to Stuff® and didn't want to let it go. He hadn't been living correctly so there was no way that he could die correctly.
It really matters what we set our hearts on. And his young son, Manasseh, learned well and stuffed all sorts of worldly things into his heart so that there was no room for the LORD God of Israel.
Where is our heart, our love and our affections? Time will tell. But don't wait till then; tend to the matter now and stoke the love and affection of God and Godly things!