The book of Galatians is a letter written by the apostle Paul to the church in the Roman province of Galatia. Paul had founded the church there on his first missionary journey. The letter was authored sometime between a.d. 51 and 53.
There were issues in Galatia with those who maintained that Christians still needed to follow the ceremonial practices of Old Testament Judaism such as circumcision. They held Paul had removed these practices from Christianity himself so as to make the gospel more appealing to the Gentiles. Paul's response is clear. We are saved by grace through faith. Nothing more, nothing less.