What does Galatians 5:7 mean?

Paul turns to a metaphor he uses often in the New Testament: running. Here, he illustrates what has happened to the Galatian Christians. They were "running well." In other words, they received the good news about Jesus with great joy. They believed that Jesus died in their place, for their sins, on the cross. By faith, they were welcomed as children into God's family. They received the Holy Spirit. They were following Christ.

Then they stumbled. Paul asks: who tripped them? Who hindered them from obeying the truth? The Galatians were being persuaded to begin following the law in order to be made right before God (Galatians 2:4). They were disobeying the truth that they were fully forgiven and accepted by God (Galatians 1:6–8). They were starting to believe the lie that they must do more to be right with their Father. He must expect more from them.

For the first time, Paul seems to focus on an individual person, instead of the group of Judaizers, in general. Perhaps he had one of their leaders in mind. Paul wanted the Galatians to identify this person as an obstacle to their relationship with God through faith in Christ.