Question: I am reading "Mere Christianity" by C.S. Lewis and just finished Chapter 12 in the 3rd section. In this chapter he is discussing the idea that we need to realize we cannot fight sin ourselves, but we must "leave it up to God". We need to trust in following the path of Christ rather than simply putting our own effort forth to stop sinning. That's all great, but I'm having a hard time with the last two paragraphs. I was hoping someone could clarify what he is trying to say.

> 
> I think all Christians would agree with me if I said that though Christianity seems at first to be all 
>  about morality, all about duties and rules and guilt and virtue, yet it leads you on, out of all that, into 
>  something beyond. One has a glimpse of a country where they do not talk of those things, except 
>  perhaps as a joke. Every one there is filled full with what we should call goodness as a mirror is filled 
>  with light But they do not call it goodness. They do not call it anything. They are not thinking of it. 
> 
> 
> They are too busy looking at the source from which it comes. But this is near the stage where the road 
>  passes over the rim of our world. No one's eyes can see very far beyond that: lots of people's eyes can 
>  see further than mine.
> 
> 
>

Answer: 
A man focused on loving others instead of himself will see the many rules shrink to but one. As Romans 13 says:

> 
> 8 Let no debt remain outstanding, except the continuing debt to love
>  one another, for whoever loves others has fulfilled the law. 9 The
>  commandments, “You shall not commit adultery,” “You shall not murder,”
>  “You shall not steal,” “You shall not covet,” and whatever other
>  command there may be, are summed up in this one command: “Love your
>  neighbor as yourself.” 10 Love does no harm to a neighbor. Therefore
>  love is the fulfillment of the law.
> 
> 
> 

An analogy I once heard was about flying an aircraft. There are many rules that are followed by the crew and imposed upon the passengers in order to make the flight safe. However, those rules have nothing to do with the purpose of flying. The purpose of flying is to get to your vacation spot, business meeting, wedding, or what-not. As you mature in the faith, the goal of your faith becomes more important, and you get less tripped up by the steps you need to take to get there.
Lewis' point is that while many Christians are focussed largely on the question of how they might avoid sin, and how they might be more moral, those who are more advanced in the faith are not thinking about those things at all. As they come to realize more completely that Jesus has paid the price of forgiveness for them, they stop thinking about those things. Instead they focus on Jesus, "the source from which it comes". They think about him, and about their relationship with him, and what he has done, and his love for them, and their love for him. In doing so they unconsciously still do the things that Jesus wants them to (what we call 'goodness'). In the very last line he opines that at this stage the Christian is usually close to passing on to be with Jesus and no longer in this world.