The text doesn't exactly say that because he showed them all that God was going to send them back to take all. The taking was because of the national sins of Judah and the prophecies of the previous chapters. Hezekiah was shown that there would at least be peace during his remaining fifteen or fewer years on earth. Why he would show them all his treasures for simply expressing concern about his prior health is to me a puzzle.
2012 - pBiblx2 Field Wise Bible System Version 2.0.9d - GPL3