"Hope is one of the Theological virtues. This means that a continual looking forward to the eternal world is not (as some modern people think) a form of escapism or wishful thinking, but one of the things that a Christian is meant to do. It does not mean that we are to leave the present world as it is. If you read history you will find that the Christians who did the most for the present world were just those who thought most of the next" (Mere Christianity, book 3, chapter 10, p. 134).
In this quote, Lewis denies that hope is simply "wishful thinking"as so many others would say. Most of the world that we live in today, as cynical as it is, would look at hope as an unrealistic, made up thing that people cling to so they don't have to face reality. However, Lewis disagrees. He explains that rather than a device used to escape reality, hope is something that can be used to better reality. Lewis states, "Christians who did the most for the present world were just those who though most of the next." When Christians do something in order to improve the world and that is their only goal, it can be expected that not much will come of it. If the world is the only thing that motivates them and they attempt to make a change on their own, how can they expect an outcome any greater than what the world already is? However, if they set their sights on God and work to please Him, then they can expect greater results because God is so much greater than anything of this world. No one should think of trying to make the world better as a bad thing. As Lewis says, "It does not mean that we are to leave the present world as it is." Although, if we go about it in the wrong way--only focusing on the worldly outcome rather than putting our hope in God and thinking of the future--then our actions will not be as powerful. Lewis expresses his idea that hope is "a continual looking forward to the eternal world." Lewis goes on to say that this is "one of the things that a Christian is meant to do." As Christians, Lewis says we have a responsibility to keep our focus on what we have to come and not put our full attention on this world. When we do this our deeds will more reflect heaven and the Lord's will instead of the will of the world.
I agree with Lewis in that hope is more than just wishful thinking. It has to be an active decision, not just a feeble desire for something better. Hope entails setting your sights on God and having faith that He will provide something better than what we currently have. I don't view hope as something that you have one day, but can lose the next. It should be a consistent state because our hope is in God and He is a consistent being. We never have to worry about God faltering, therefore if our faith is in Him, our hope should not falter. I've never really thought about hope in the way that Lewis talks about it though. I haven't really thought about our hope helping us make changes to the world. I also never thought of hope as a virtue. My previous view of what hope was was more simple. I thought of it as us trusting that God has something better in store for us but I didn't think of it as something that "Christian[s are] meant to do." I didn't put it on that high a level. I think that if people have "hope" in what we have ahead of us, it could potentially give them an excuse to not care about what happens in this world. If a person is only focused on the future then why would they care what happens in this life? However I realize that this is the incorrect way to look at what hope should be. It should be that when we look to the life ahead of us it inspires us to try to better this life. That in itself can be a testimony to others and could help bring people to Christ, further improving their life in the world.