What does Acts 5:2 mean?

Ananias and Sapphira are two recent converts to the early church in Jerusalem. They're swept up in the communal altruism meant to provide for those who are financially struggling. This likely included a number of new believers from other cities and nations who don't have access to their assets (Acts 4:32–37). Like Barnabas, they sell a piece of property and give the proceeds to the apostles. Their motivation, however, turns out to be less than pure.

"Kept back" is from the Greek root word nosphizō which also means to embezzle. The same term is seen in Titus 2:10, where the ESV renders it as "pilfering." The point, then, is that this married couple is dishonestly representing their gift. The problem isn't that Ananias and Sapphira had to give the church all the proceeds. The sin is in lying to the Holy Spirit (Acts 5:3). Apparently, they vowed they would donate all the money and then secretly went back on that oath. Jesus points out that the Mosaic law said, "You shall not swear falsely, but shall perform to the Lord what you have sworn" (Matthew 5:33). He goes on to say we shouldn't make oaths to God, anyway; merely do what we say we will (Matthew 5:34–37). Their vow was unnecessary (Acts 5:4), but since they made it, they needed to either keep it or at least be honest about having made a mistake.

More to the point, Ananias and Sapphira seem to want the prestige of charity without the actual cost. Rather than simply admitting that they were giving part of the proceeds, they put on a show of piety.

God doesn't mandate Christians to give away all our possessions. Jesus' often-mentioned challenge to the rich young man was specific to him because despite his love for other people, the man valued his money more than God (Mark 10:17–22). When we give to God's work, we need to give as we decide in our hearts (2 Corinthians 9:7), not to impress others, but in worship to God (Mark 12:41–44).