Galatians 2

Peter has been taking the gospel to the Jews and Paul to the Gentiles. Jewish converts in Jerusalem were still keeping the Law of Moses in some ways and were critical of the gentile converts who were not. The Jewish converts insist that Titus, who has been with Paul, should be circumcised and Peter evidently agrees with them. Paul is adamant that he shouldn't be and a disagreement arises between the two apostles. Paul stands firm and is right. It's good to see that these two great men and apostles are human, that they can disagree while carrying on the work. And in this case, it is a matter of perspective. Peter has been in Jerusalem with the Jews continually. Paul has been away and among the gentiles. And eventually, the matter is be settled between them.

Paul talks of justification and works saying that works will not justify us. The works he is specifically talking about are the works of the Law of Moses. Justification is where Christ states that where we were once guilty we are now innocent. We cannot justify ourselves, it can only come through Christ because the his mercy (grace) he grants us. Justification isn't earned through the ritual of doing works of a law. But some action is expected. We do have to accept the gospel, accept Christ and strive to live righteously if we want to experience that grace because more is involved than justification. Nephi says, we are saved by his grace after all that we can do. While justification pronounces us innocent, it does not change our natures. Sanctification by the Holy Ghost is what changes our nature so these two, justification and sanctification, must go hand in hand. One is a pronouncement, the other is a process. One says we are worthy while the other makes us holy. That is why living righteously is so important because it is through our righteous living that the Holy Ghost enters our lives and sanctifies us from all unholiness.