Lift up your eyes to the heavens, and look on the earth beneath: for the heavens shall vanish away like smoke, and the earth shall grow old like a garment, and they that dwell therein shall die in like manner; but my salvation shall be forever, and my righteousness shall not be abolished. (Isaiah 51:6, DARBY)
The message here isn’t — of course — that the created dies but that the Creator lives forever and that His purposes never fail. The heavens above us — the sky, the other planets, the stars, the galaxies — will vanish one day like a puff of smoke. And the earth will just wear out. So will we. We will grow old and die. Some translations go so far as to say we will die like gnats or like flies — like insignificant insects.
But God — who is not insignificant — will never die. And His holiness and His method of salvation will last forever.