When Frodo is first entrusted with the ring, it was a great responsibility. The responsibility and sacrifice were too much for many. He first objected thinking that he didn't deserve such a responsibility. Gandolf told him he must. He then tried to pass the responsibility back to Gandolf who rebuked him saying: "Don't tempt me, Frodo! I dare not take it. Not even to keep it safe. Understand, Frodo. I would this ring from a desire to do good... But through me, It would wield a power too great and terrible to imagine" (Imdb.com). So thus Frodo becomes the ring bearer.
We are all entrusted with a ring of sorts. We are given stewardship over the souls of mankind. That is our responsibility. Some may say that it is too great for even the greatest of men and women. But it is our task. We must carry the responsibility with dignity and pride for it is our calling. I am not just talking to missionaries but to all of us. As we live to that which we are entrusted and do the things that the Lord wants we like Frodo will receive our reward when the ship into the West comes.