What does Galatians 4:18 mean about being zealous only when Paul was present?

Galatians 4:18 means zeal for the good thing should be continual, not only when Paul was physically present. The Galatians held together while he was with them, but once he left, false teachers entered like ravening wolves and tore the congregations apart, showing their zeal depended on his presence.

Les explains that the Galatians were being influenced by Judaizers who demanded circumcision and law keeping, opposing Paul's pure Gospel of Grace. Paul asks them to be zealously affected always in a good thing, not only when he was present. When he was physically with them, they could hold everything together, but as soon as he was gone, false teachers came in like ravening wolves and tore the little congregations apart. The perverters eventually succeeded, as Paul later wrote that all in Asia, including Galatia, had turned against him. The lesson is that zeal must be constant and not dependent on a teacher's presence.

Galatians 4:18

But it is good to be zealously affected always in a good thing, and not only when I am present with you.

What happened to the Galatian congregations when Paul was not physically present?

When Paul was absent, false teachers entered like ravening wolves and tore the Galatian congregations apart. The Judaizers persuaded them toward circumcision and law keeping, pulling them from the pure Gospel of Grace into a perverted gospel that troubled them.