13 You, my brothers and sisters, were called to be free. But do not use your freedom to indulge the flesh; rather, serve one another humbly in love. 14 For the entire law is fulfilled in keeping this one command: “Love your neighbor as yourself.” 15 If you bite and devour each other, watch out or you will be destroyed by each other.Here Paul continues the argument begun at the start of chapter 5. Specifically, the opening verses tie back to 5:6. Paul's main goal here is two-fold. He wants to deal with actual problems in Galatia and head off criticism of his gospel. It appears that the Galatians were having problems within the community. They weren't displaying the love and other regard that communities led by the Spirit should display. Paul know he needs to correct this, especially as the Teachers had come in and seen the problems and proposed a solution: Torah. Torah would act both to restrain behavior but also act as the source of identity.
16 So I say, walk by the Spirit, and you will not gratify the desires of the flesh. 17 For the flesh desires what is contrary to the Spirit, and the Spirit what is contrary to the flesh. They are in conflict with each other, so that you are not to do whatever you want. 18 But if you are led by the Spirit, you are not under the law.
19 The acts of the flesh are obvious: sexual immorality, impurity and debauchery; 20 idolatry and witchcraft; hatred, discord, jealousy, fits of rage, selfish ambition, dissensions, factions 21 and envy; drunkenness, orgies, and the like. I warn you, as I did before, that those who live like this will not inherit the kingdom of God.
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. 26 Let us not become conceited, provoking and envying each other.
Paul will have nothing to do with that line of thinking. The Galatians were freed from the law. However, that freedom wasn't freedom to do whatever they wanted. It was to serve one another in love. The Galatians had been told this before, but it hadn't fully settled. Perhaps the explicitness of the law had appeal to the Galatians. But even then, a life of service to one another in the Spirit fulfills the law. Paul recognizes God's will in the law, but insists that it's fullest expression is the command to love (so Fee). The Galatians just needed to be reminded and buy in.
Paul goes on to contrast two lists, one of virtues and the other of vices. It's absolutely critical that we see that these identify community traits. Communities that are lead by the Spirit don't look like 'x' but like 'y.' This comes through very clearly when we look at the list of vices. Eight of the fifteen items deal with obviously interpersonal issues. Yes the individuals in the communities need to have the fruit of the Spirit for the community to exhibit it, but it must be exhibited at the community level. Discipleship is not an individual matter. The church is a discipleship collective.
I am going to refrain from commenting on the lists individually as I think it's fairly clear what most of the vices and virtues are. Paul closes by reinforcing what he said previously, but he makes an important clarification along the way. By contrasting the works of the flesh and the fruit of the Spirit it may mislead one to think that discipleship is a passive process. Verse 24 should show how mistaken that thinking is. We are active participants, crucifying the things that would lead to a community that is out of step with the Spirit and reflects our sinful tendencies.