What happens if you preach a false gospel?

I love Paul's letter to the Galatians. It's a church formed from his preaching, a people who warmly embraced him and the gospel he preached. However, some time later they have changed direction. Paul diagnoses this as a move from freedom to slavery. That freedom was won by Jesus in his death and resurrection to set them free from the slavery of the present evil age (1:3-5), which manifests in religion and idolatry (1:14-15,4:8). At the outset he takes on the magnitude of preaching a false gospel, which is his charge against the cross-avoiding (6:11) preachers who have arrived in the church. I'm riffing on some observations Justin Taylors blog a few weeks ago here:

What happens if you preach a false gospel? (v6)

• God is deserted (1:6). Departure from the gospel is to depart from God himself. This is why it really matters. Adopting a different gospel means we've adopted a relationship with a god who isn't there, who doesn't exist. By contrast, the gospel brings us to God.
• The gospel is distorted (1:7). False gospels effect the gospel, they distort God's message of good news and replace it with a non-gospel, a message that isn't good news.
• The preacher is damned (1:8). Those who preach false gospels commit a grievous crime but more than that we always preach what we believe, so to preach a false gospel is to believe such a false gospel which takes us away from God. Without belief in this gospel there is no deliverance since no-one has given themselves for our sins, we remain under wrath - condemned. By contrast the true gospel preacher knows God's favour.
• The church is disturbed (1:7). The false gospellers trouble the church, it is upset and blown around by the erroneous message. By contrast the true gospel gives the church solidity, substance and maturity.
• The world is delighted (1:10). People are pleased by false gospels. That a message is popular proves nothing either way but part of the trouble of false gospels is that they do tell people what they'd like to hear, whereas the true gospel is offensive, provoking persecution and mockery. That said, the gospel can be expected to bear fruit as it did in Galatia.

A letter beginning this way will ruthlessly expose false gospels but is going to want to draw our attention to the gospel, the one Paul portrayed as "Christ crucified" (3:1) and reflecting his boasting in nothing but the cross (6:14) that revels in freedom (5:1) and inheritance (4:7) that come from the gospel.  That's not to say that this letter is harsh and cold - Paul loves the Galatians, he preached to them, he cares for them like a parent and is bewildered at their change of direction. He is bold but kind, careful and convincing as he draws them back to the gospel of Jesus by proclaiming again that gospel.