It's striking that in different parts of the world, Christianity is seen as strongly associated with different political ideologies. In the US, it's usually seen as associated with right-wing republicanism. In South America, it's usually seen as associated with left-wing liberationism. In the UK, at least since WW2, it's often seen as associated with moderate socialism. Part of that of course, is to do with what the issues of the day are in those countries and what the traditions of Christianity that are dominant in those countries say on those issues.
So, in the US for example, the dominant issue often seems to be the Culture Wars – one group trying to liberalise culture in issues of homosexual rights, teaching of evolution, etc and the other side trying to make it more conservative on issues of abortion, etc. I do have things I think about that (and it is not the classic US Christian Right view), but they can with for another time. Instead, I'd like to give a quick outline on what I read the Bible as saying about social justice.
A large proportion of the Bible's teaching on this is aimed specifically at the context of Ancient Israel, which was an overwhelmingly subsistence-level agricultural Iron-Age society. But there are some good general principles.
For a start, all Israelites had land, which was seen as belonging to that family, in some sense, for ever. So they could sell the land, but it reverted back to them after a period. In essence, they had an inalienable and unsellable freehold on the land. If they went completely into debt, they could sell their land and even sell themselves into servitude, but in both cases they became free automatically (unless they ask not to!) and their land went back to their possession automatically. This meant that everyone who could work was able to work to produce their own food. It's not state handouts – it can't create a culture of dependency.
Because land was usually, but not always, held by the (male) heads of family, it was possible for people to “fall out” of the system – the widows, the fatherless, etc. There were therefore specific laws forbidding farmers from harvesting their own crops too thoroughly and giving the dispossessed the right to “clean up” after them. So even the least in society get provided with food, but need to work for it.
The whole idea of land being tied to families also means that the idea of the family is very important. So if there were elderly people who could not work, or young children, or disabled people, etc, they were cared for primarily by their family – who they're less likely to take advantage of. There wasn't any concept of “state handouts”, but there was a lot of legal support and protection for the family, to the extent that crimes “against the family” were punished very severely.
It's interesting thinking about how this applies to modern systems of social security, for example. It puts a great ideal forwards – that everyone should be supported by their own work or by that of their family. All too often, left-wing systems emphasise that “everyone should be supported” and create a culture of sponging dependency, whereas right-wing systems emphasise that it should be “by their own work” and allow people to fall through the gaps. The system in ancient Israel (about 3000 years ago) seems to avoid both dangers.