I love this passage in Mere Christianity in which Lewis talks about whether the Christian life is hard or easy.

It’s both, Lewis says. It’s hard as death in the beginning, and then as his life begins to worth within us and transform us, it is relatively easy, because he does the work of transforming us.

We are to hand ourselves over to Christ, to be ploughed up and resown. We are to have the bad tooth out, and a new tooth given us. It’s like death.

But then, He lives within us and helps us to do impossible things. In that way, it’s easy.

And–and this is the insight I love–once we surrender ourselves to Jesus, and rely on his strength within us to get through our days, it’s fine, it’s normal, if we only succeed for moments at a time. You surrender yourself to Christ, you rely on his strength. Perhaps, relying on it, you will bite back one unkind retort; silence a bit of juicy gossip; not respond to provocation; pass up the chocolate you do not need; close the laptop when you’re wasting time on the internet. And then, you might blow it.

But “from those moments of victory, a new sort of life is spreading through your system,” and that too is a way in which sanctification works.

Surrendering ourselves to Jesus for moments at a time. Relying on his strength for moments at a time. Even the weakest Christian, such as I often am, can do that? And a lifetime is made up of moments!!

Mere Christianity, Chapter 30, 
Is the Christian Life Hard or Easy?

In the previous chapter we were considering the Christian idea of ‘putting on Christ,’ or first ‘dressing up’ as a son of God in order that you may finally become a real son. What I want to make clear is that this is not one among many jobs a Christian has to do; and it is not a sort of special exercise for the top class. It is the whole of Christianity. Christianity offers nothing else at all.  ’.

 The Christian way is hard, and easy. Christ says `Give me All. I don’t want so much of your time and so much of your money and so much of your work: I want You. I have not come to torment your natural self, but to kill it. No half-measures are any good. I don’t want to cut off a branch here and a branch there, I want to have the whole tree down. I don’t want to drill the tooth, or crown it, or stop it, but to have it out. Hand over the whole natural self, all the desires which you think innocent as well as the ones you think wicked – the whole outfit. I will give you a new self instead. In fact, I will give you Myself: my own will shall become yours.’

 Both harder and easier. You have noticed, I expect, that Christ Himself sometimes describes the Christian way as very hard, sometimes as very easy. He says, ‘Take up your Cross’- in other words, it is like going to be beaten to death in a concentration camp. Next minute he says, ‘My yoke is easy and my burden light.’ He means both. And one can just see why both are true.

Teachers will tell you that the laziest boy in the class is the one who works hardest in the end. They mean this. If you give two boys, say, a proposition in geometry to do, the one who is prepared to take trouble will try to understand it. The lazy boy will try to learn it by heart because, for the moment, that needs less effort. But six months later, when they are preparing for an exam, that lazy boy is doing hours and hours of miserable drudgery over things the other boy understands, and positively enjoys, in a few minutes. Laziness means more work in the long run. Or look at it this way. In a battle, or in mountain climbing, there is often one thing which it takes a lot of pluck to do; but it is also, in the long run, the safest things to do. If you funk it, you will find yourself, hours later, in far worse danger. The cowardly thing is also the most dangerous thing.

It is like that here. The terrible thing, the almost impossible thing, is to hand over your whole self – all your wishes and precautions – to Christ. But it is far easier than what we are all trying to do instead. For what we are trying to do is to remain what we call ‘ourselves,’ to keep personal happiness as our great aim in life, and yet at the same time be ‘good’.

We are all trying to let our mind and heart go their own way-centred on money or pleasure or ambition–and hoping, in spite of this, to behave honestly and chastely and humbly. And that is exactly what Christ warned us you could not do. As He said, a thistle cannot produce figs. If I am a field that contains nothing but grass-seed, I cannot produce wheat. Cutting the grass may keep it short: but I shall still produce grass and no wheat. If I want to produce wheat, the change must go deeper than the surface. I must be ploughed up and re-sown.

That is why the real problem of the Christian life comes where people do not usually look for it. It comes the very moment you wake up each morning. All your wishes and hopes for the day rush at you like wild animals. And the first job each morning consists simply in shoving them all back; in listening to that other voice, taking that other point of view, letting that other larger, stronger, quieter life come flowing in.And so on, all day. Standing back from all your natural fussings and frettings; coming in out of the wind.

We can only do it for moments at first. But from those moments the new sort of life will be spreading through our system: because now we are letting Him work at the right part of us. It is the difference between paint, which is merely laid on the surface, and a dye or stain which soaks right through. He never talked vague, idealistic gas. When he said, `Be perfect,’ He meant it. He meant that we must go in for the full treatment. It is hard; but the sort of compromise we are all hankering after is harder – in fact, it is impossible.

It may be hard for an egg to turn into a bird : it would be a jolly sight harder for it to learn to fly while remaining an egg. We are like eggs at present. And you cannot go on indefinitely being just an ordinary, decent egg. We must be hatched or go bad.

May I come back to what I said before? This is the whole of Christianity. There is nothing else. It is so easy to get muddled about that. It is easy to think that the Church has a lot of different objects education, building, missions, holding services. The Church exists for nothing else but to draw men into Christ, to make them little Christs. If they are not doing that, all the cathedrals, clergy, missions, sermons, even the Bible itself, are simply a waste of time. God became Man for no other purpose.

It is even doubtful, you know, whether the whole universe was created for any other purpose. It says in the Bible that the whole universe was made for Christ and that everything is to be gathered together in Him. I do not suppose any of us can understand how this will happen as regards the whole universe. We do not know what (if anything) lives in the parts of it that are millions of miles away from this Earth. Even on this Earth we do not know how it applies to things other than men. After all, that is what you would expect. We have been shown the plan only in so far as it concerns ourselves.

I sometimes like to imagine that I can just see how it might apply to other things. I think I can see how the higher animals are in a sense drawn into Man when he loves them and makes them (as he does) much more nearly human than they would otherwise be. I can even see a sense in which the dead things and plants are drawn into Man as he studies them and uses and appreciates them. And if there were intelligent creatures in other worlds they might do the same with their worlds. It might be that when intelligent creatures entered into Christ they would, in that way, bring all the other things in along with them. But I do not know: it is only a guess.

 What we have been told is how we men can be drawn into Christ – can become part of that wonderful present which the young Prince of the universe wants to offer to His Father – that present which is Himself and therefore us in Him. It is the only thing we were made for. And there are strange, exciting hints in the Bible that when we I are drawn in, a great many other things in Nature will begun to come right. The bad dream will be over: it will be morning.