בַּיָּמִ֣ים הָהֵ֔ם חָלָ֥ה חִזְקִיָּ֖הוּ לָמ֑וּת וַיָּבֹ֣א אֵ֠לָיו יְשַׁעְיָ֨הוּ בֶן־אָמ֜וֹץ הַנָּבִ֗יא וַיֹּ֨אמֶר אֵלָ֜יו כֹּֽה־אָמַ֤ר יְהוָה֙ צַ֣ו לְבֵיתֶ֔ךָ כִּ֛י מֵ֥ת אַתָּ֖ה וְלֹ֥א תִֽחְיֶֽה׃
In those days was Hezekiah sick unto death. And Isaiah the prophet the son of Amoz came to him, and said unto him: ‘Thus saith the LORD: Set thy house in order; for thou shalt die, and not live.’
Read halakhic rulings (Jewish law) on II Kings 20:1: and classical halakhic sources.