Galatians 5:22-25
22 But the fruit of the Spirit is love, joy, peace, forbearance, kindness, goodness, faithfulness, 23 gentleness and self-control. Against such things there is no law. 24 Those who belong to Christ Jesus have crucified the flesh with its passions and desires. 25 Since we live by the Spirit, let us keep in step with the Spirit.
What is the significance that these qualities are called the "fruit of the Spirit"?
It says that those who belong to Christ have crucified the flesh. But, it seems that many who claim to be believers have not crucified the flesh at all, but look much like the world. What is the significance of this?
How do you live by the Spirit?
In the context of what Jesus said about branches bearing fruit, about vines being tended, and about branches that bear no fruit being thrown into the fire, I think there's an indication that if we are "attached" to Jesus we will bear fruit, and if we do not bear fruit people would be right to question just how, and indeed whether, we are walking with Jesus.
Jesus' comments about false prophets performing great miracles and how we would know them by their fruits, coupled with Paul's comments in 1Co 13 about how it doesn't matter what we do because if we have no love (one of the fruit, even if not listed here) it's all to no avail, shows how we shouldn't be taken in by things that suggest someone may walk closely with God if they are lacking the things that should be there.
Paul's comments about the gifts being given by the Spirit, as he decides show that not everybody has every gift, and indeed implies that some people may not have supernatural gifts at all. The fruit should be evident in the life of every Christian - someone who has love and peace but does not prophesy is most likely in a better place spiritually than someone who prophesies and speaks in tongues but is full of wrath and envy.
Looking much like the world can be a tricky one, simply because Christians need to be in the world. We wear clothes, we do grocery shopping, we meet our friends for a beer, we pursue hobbies, we do many of the same things that "the world" does. What should set us apart is the fruit, the hope that we have within us, and often it's the little things that people notice. If you're the only one in the office who doesn't swear like a drunken sailor, if you're the one who is honest with your expense claims, if you're the one who would rather fail an exam than pass by cheating, people notice. They might not say anything, but they notice.
The world's way is often little more than "fake it 'til you make it". Living by the Spirit is something that improves with time, as we do more and more of it. I think it's 1Peter chapter 1 (don't have a Bible to hand right now) that describes what is essentially a progression of holiness. It might be boiled down to "don't run before you can walk". I've often thought of us as being like shapes with jagged bits stuck on the sides, and the Christian life as being like a succession of holes that we don't fit through unless a bit gets broken off. With each hole we have the opportunity to crucify a little more of our flesh, lose a little more of ourselves that isn't Christ-like. Each one of us has a different walk, so for some of us it might be that the holes are easy to pass through and come at wide intervals while for others some holes may be painful and they may come more frequently, but ultimately the goal is the same - to make us ever-more like Jesus.