Kabbalah zu Jeschijahu 38:11

He began by saying, "I said, I shall not see Kah; Kah, in the land of the living; I shall behold man no more with the inhabitants of cessation" (Isaiah 38:11). How obtuse, he said, are the people who do not know or pay heed to the words of the Torah, but look only upon worldly matters. The spirit of wisdom is forgotten from them.

And what was the reason for all this? Because the prophet told him, "for you shall die" in this world "and not live" (Isaiah 38:11) in the World of Truth. For, upon death, he who has not begotten any children in this world is expelled from all that is mentioned above and cannot stay to gaze upon that shining light. If this was the case with Hezekiah, who was a pure, righteous man, so much more for those who do not have ancestral merit to support them and have even sinned before their Master.