What does Acts 5:17 mean?

Despite direct orders from the high priests (Acts 4:17–18), the apostles are in the temple courtyard, teaching that Jesus rose from the dead. And despite Peter and John's arrest and release, more and more people are following Jesus (Acts 4:1–3, 21; 5:14).

The Greek term translated "jealous" here is zēlos, which implies a fierce, passionate emotion. It can mean a potent desire or love for something, or to want what someone else has. When God says He is "jealous" for us, it is because we rightfully belong to Him (Exodus 20:5). Paul also says this to the church members in Corinth when they follow false teachers (2 Corinthians 11:2). The priests may feel that their jealousy is righteous; they certainly feel these Jesus-followers are pulling the people away from their leadership and theology, as did Jesus (Matthew 27:18). But they don't have their mind on the big questions: Are the apostles leading people toward or away from God? Are the apostles or the priests leading the people closer to God? Does the priests' jealousy align with God's righteous jealousy? Is it possible these men are telling the truth?

Sadducees are members of a specific Jewish sect, in contrast with the Pharisees, Essenes, and Zealots. Most members of the priesthood and Sanhedrin are Sadducees. These men approve of Roman rule and don't follow the extra-scriptural teachings of the Pharisees. Unlike the Pharisees and the Jesus-followers, Sadducees don't believe in the resurrection of the dead (Mark 12:18). Not only is the apostles' teaching contrary to one of their most sacred beliefs, they are teaching that Jesus, their enemy whom they had killed, is alive. Right now, this works against the apostles. Later, Paul will use this distinction between the Sadducees and Pharisees to get out of a meeting before the Sanhedrin (Acts 23:6–10).