Human understanding of reality changed in 1923 when our species did what Isaiah 51:6 suggests, and looked (in)to the heavens and looked at (the structure of) the earth ... and learned that ALL physical existence is only temporary. Temporary like the Sukkot we build each year: a house "not built to last" and that will one day cease to exist. We are we to do with this knowledge in contrast to the "eternity" of what God calls, "My Salvation/Rescue" ("Yeshua-ti") in the very same verse? How does knowledge of transience fit in with "Sukkot, the season of our rejoicing?"