The third volume in Tolkien’s Lord of the Rings series is titled The Return of the King, referring to Aragorn’s assumption of the throne of Gondor once the ring has been destroyed and the evil of Mordor vanquished. Up to this point, Gondor has been ruled by a man named Denethor, who holds the hereditary title and position of Steward of Gondor, the one who oversees the running of the kingdom and keeps it going on behalf of the king. When Gandalf arrives on the eve of battle, it is clear that the Stewards have been in power so long - it has been many centuries since a king last sat on the throne - that their true purpose has been forgotten and they have all but become out-and-out rulers.
Gandalf calls Denethor on this: “Unless the king should come again?...Well, my lord Steward, it is your task to keep some kingdom still against that event, which few now look to see.” Gandalf deliberately uses his title, Steward, which comes from two Old English words meaning “house” or “hall” and “keeper” or “guardian” (as Tolkien well knew and most certainly had in mind). Yes, Gandalf knows something that Denethor does not: Aragorn, Isildur’s heir, the rightful King, is on his way. Still, that should not make a difference - Denethor should be doing everything in his power to preserve Gondor and protect it from the forces of evil so that there is a Gondor left to turn back over to the king, whether he shows up tomorrow or in another several centuries. Instead he is exploiting his position of power and has become a king (and not a very good one, it seems) in all but name, taking on all of the trappings and privileges and power without also taking on the responsibility of caring for the people.
Unfortunately, the example of the bad steward seems to be the one that humans have been wont to follow as long as we have walked upon this earth. Not even Adam and Eve fulfilled their duties as stewards of the beautiful garden into which they were placed. They took it upon themselves to do whatever they wanted instead of what God asked them to do, and because they thought they knew it all, they ate from the one tree he said to leave alone. We have been exploiting our home ever since, oftentimes more concerned for our own comfort and wealth than for leaving something worth having for the generations that will follow us.
We are stewards - keepers or guardians of this planet God has given us to call our home. What will it take for us to really be true to that name?