Things that will last are from god
and have eternal significance,
whereas everything else disappears.
In Isaiah chapter 51, verses 5 and 6 the LORD says: “My righteousness draws near, my salvation has gone out, and my arms will judge the peoples; the coastlands hope for me, and for my arm they wait.” Then the LORD says the heavens will vanish like smoke and the earth will wear out like a garment, etc. But look closely at what lasts through it all: “But my salvation will be forever, and my righteousness will never be dismayed.”
Everything we know in this life will one day disappear, except for one thing. That is the forgiveness of sins through Christ our Lord.