Because the (creation) itself also shall be delivered from the bondage of corruption into the glorious liberty of the children of God (Romans 8:21).
This is the first of eleven occurrences of the noun liberty (Greek, eleutheria) in the New Testament. The Christian patriot, Patrick Henry, became famous for his liberty or death speech that helped spur the American people on to liberty from their British bondage. Three millennia earlier, the children of Israel had been delivered into liberty from bondage in Egypt. But the greatest deliverance of all will be when Gods mighty universe, now groaning under its great curse of decay and death because of sin (here called the bondage of corruption), will be delivered into the glorious liberty already shared by the redeemed children of God.
When Adams sin brought death into the world (Romans 5:12), God had to curse the very dust of the ground for mans sake (Genesis 3:17). That is, the basic elements of the physical universe out of which all material substances had been formed have been placed in bondage to a law of decay, with every substance tending toward disintegration and death. In science, this principle is called the law of increasing entropy (or disorder) and is acknowledged as one of its most basic and certain laws.
But the Creator who imposed the curse has also paid the price to deliver His creation, becoming man, Himself, then dying for mans sin, and defeating death by His resurrection.
One day soon the creation will experience its own glorious freedom when Jesus comes again. As Moses once led Israel out of bondage, and Washington led America to its freedom, so Christ will deliver His redeemed creation into glorious liberty, forever. HMM