Paul had preached the Gospel to the Galatians , Galatians were pagans and he had preached to them about the death and resurrection of Jesus, he was teaching them the truth, the freedom they receive when they accept Christ, but the Judains came and they started to teach them Law, now before Christ came into this world and before he was sacrificed for us and during the times of Moses they were given these laws which made them aware of their sin, but in they failed to realize and put these laws above God, and now they were coming to the Galatians and trying to confuse them giving them the laws that were given to them, and as they refused to accept Jesus they wanted the Galatians also to follow laws and not accept the truth that Jesus died for all to give us eternal life thru him. Thus they were preaching wrong versions to the Galatians and putting them in confusion.