A fifth element of early Christian fellowship was sharing each others possessions with those who were in need (2:45). We hear an example at the end of Acts 4. Barnabas, who would go with Paul on some of his missionary journeys, apparently had an extra field. He sold it and gave it to the apostles to use in order to serve others in the community who were in need.
Barnabas was not forced to sell the field. In Acts 5 when a couple lie about how much they sold their land for, Peter makes it clear that they were not forced either to sell their land or give it all to the disciples (5:1-4). To argue over such things is to miss the point. Acts pictures a community where people wanted to help those in need around them and were willing to share their own possessions to make it happen.
They did not think of their possessions as being their own (4:32). True, they may have thought that the kingdom of God was about to arrive. But they demonstrated an attitude that is strongly and consistently affirmed throughout the New Testament. Christians are not hoarders. They are sharers.
And this attitude makes sense if the church is like a healthy family. What ideal father and mother does not help their children out when they are truly in need? What brother or sister would not help the other out if the need is legitimate? Many of us have aunts and uncles or cousins who would do the same.
Help of course can come in more than just material form. Help can be sharing knowledge or skills. Help can be training people to help themselves.
Of course we can also use these as excuses. Human nature is very good at rationalization. We can pretend to be sharing when we are not, like Ananias and Sapphira in Acts 5. Or we can point out technicalities of Acts to justify an unsharing attitude. God knows the difference. You cannot lie to the Holy Spirit.
In Acts 5, Ananias and Sapphira pretend to be generous. They sell some property and act as if they are giving it to the community. The Holy Spirit tells Peter that they are pretending, that they are lying. Peter does not rebuke them for not giving all. He rebukes them because their heart was wrong.
Ananias immediately falls over dead, and when his wife hears what happened she does as well. It is a reminder that God administers discipline in the new covenant as well as the old. There are plenty of people in the church today who are pretending to be righteous. It would be surprising if such individuals did not go to church. But we should always keep in mind that God knows the difference, even if we can fool those around us much of the time.
A striking line is that, "No one claimed that any of their possessions was their own, but they shared everything they had" (4:32). Such words can spark strong feelings in Americans who lived through the Cold War, where the greatest enemy of the United States was communist Russia. The Korean War and the Vietnam War were both fought against communist states. Suffice it to say, many Americans have a deeply ingrained hatred of communism.
And Acts 4:32 sounds like communism, whose founding motto was, "From each according to his ability, to each according to his need."  To some this motto will sound noble, to others it will sound unfair--shouldn't I get more if I am able to do more (cf. Matt. 20:1-16)? Enter rationalization, like the argument that it is no surprise the Jerusalem church found itself needing material support a few years later when Paul and others took supplies down to Jerusalem from Antioch.
Of course these debates go far beyond anything this verse was saying. The communism of Russia and Eastern Europe did not make its people better off. In fact, it never even really managed to become truly communist in the sense of Karl Marx, the founder of the modern idea. These countries were really dictatorships--and economic failures.
And as is often pointed out, the early church did not do away with individual property. Rather, they had a giving attitude that caused each person to share from their overflow with the needs of others. Sacrificial giving--where you share in a way that causes you to be uncomfortable--is also Christ-like. No one was forced to share, but that doesn't mean giving wasn't the right thing to do. Not sharing can disqualify someone from the kingdom of God (cf. Matt. 25:31-46).
If we can listen to the biblical text with cool heads, the problem with communism is that it does not work in the real world as an economic system. The idea of each working as they are able and giving away all their extra to those in need is thoroughly Christian. But human beings are selfish. We are often not motivated without the promise of personal gain.
Capitalism feeds off our lust and greed for more--that is why it works. It builds off of human materialism and self-interest. But ironically, if it is carefully watched and implemented, it can create an economic context in which everyone has more to share and fewer people suffer economically.
But it is important for Christians to remember that this is not because its underlying values are Christian or ideal. It is rather its potential results that can be helpful to others. We find ourselves in the ironic situation where the values of communism are more Christ-like, but do not usually result in a better world. Meanwhile, the typical values of capitalism are devilish, but can result in a more loving world if its implementation is carefully watched.
 Karl Marx, The Communist Manifesto.