Whoever loves his fellowman has obeyed the Law. Let no debt remain outstanding, except the continuing debt to love one another, for he who loves his fellowman has fulfilled the law. If you love your fellow man you have carried out your obligations. No Christian ever escapes the indebtedness to love another Christian. Whoever loves his fellow man will never do him wrong.
Love bans hurtful treatment.
Then immediately in chapter 14 Paul made application of this responsibility to love brothers with tender affection doing them no harm. The Gentile Christian who eats meat is not to look down on or despise the Jewish Christian who does not. The Jewish Christian who does not eat meat is not to pass judgment on or condemn the Gentile Christian who does. They are not to pass judgment on each other in regard to the holy days each does or does not keep. Both of them are following their consciences in expressing their faith in God.