The grace of our Lord Jesus Christ be with your spirit, Amen. The Judaisers who followed Paul wherever he went, were attempting to destroy his gospel message of grace. This is what Paul is referring to when he calls for a curse upon those who preach a gospel other than that which the apostles had been given to preach. The Judaisers were telling Gentile believers that they had keep the law of Moses, which essentially meant they must become Jews through circumcision. They were doing was undermining God s message to the world.
Biblical salvation is a message of grace.
There is no way under God's green heaven than a person can merit salvation. The apostles made this very plain. The prophets made this very plain. They had not done the will of the Father. The gospels very plainly tell us that it is the Father's will that we trust in the Son and yield to His Lordship.