What does 1 Thessalonians 2:13 mean?

And here’s something else we’re grateful for: when you heard God’s message from us, you didn’t treat it like just another human idea. You accepted it for what it really is—God’s own word—and it’s still working in everyone who trusts him. 1 Thessalonians 2:13 - Modern Text Bible

(Paul is thankful that the Thessalonians recognized the gospel as truly coming from God, not just from people, and that it’s making a real difference in their lives.)