Barnabas was one of a bunch of people who sold their possessions in order to give to the poor. We read later in Acts about how he traveled and served God wherever God called him to. A great example! The weird, freakish thing was when a couple of people - Ananias and Sapphira - tried to look like people who were giving it all but were actually holding back for themselves. What got them in trouble wasn't that they held back some of the money they'd got for selling some land, it was that they lied about it. They wanted the credit for something that wasn't true.
God did not want to see hypocrisy and deceit becoming the new normal in His Church, so He made it pretty clear that this kind of behaviour was not OK and not safe. It's still not safe today. Sure, God might not cause people to die so dramatically very often, but those kinds of attitudes still produce stunted disciples and turn others away from Jesus. God showed his love for the early church and for Ananias and Sapphira by disciplining them and stopping the poison before it spread. He still shows His love for us today by disciplining us when we need it so that we learn not to hold on so tightly to the stuff of this world - so our lives can be purified for His service. If God did nothing, Ananias and Sapphira's legacy could have been that they started a corrupting trend in the church. Because He did something, their legacy is that many people grew in respect and reverence for God and the church continued to grow. If we assume that Ananias and Sapphira were genuine believers in Jesus who made a poor decision together, we can say that in eternity they will be glad that God intervened the way He did, even though they must be sad that their behaviour made it necessary for Him to do so.
