What does the Bible say about perverting the gospel?

In Galatians 1:6-9, Paul expresses his astonishment at how quickly the Galatians have turned away from the grace of Christ to a different gospel, which he emphasizes is no gospel at all. He strongly condemns any such alteration, stating that if anyone, even an angel from heaven, preaches a gospel contrary to what he has preached, let him be accursed. This underscores the seriousness of adhering to the true gospel and the dangers associated with any perversion of it. The integrity of the gospel is critical to maintaining the glory of God and the essence of salvation.