The theme of the liturgy is the law of God. God’s law is just, it demands careful observation, and it is the key to life on earth. It is not a matter of clinging to what is human tradition but rather of practicing justice: “He who does justice will live in the presence of the Lord.”
The Pharisees misunderstood what the law was all about, or as Isaiah foretold, “they teach as dogmas mere human precepts.” For them obeying the law meant such things as “scrupulously washing their hands and the washing of cups and jugs and kettles.”
James, on the other hand, understood the meaning of the law of God, and he provides us with a pointed definition of the religion of Yahweh/Jesus: “Looking after orphans and widows in their distress and keeping oneself unspotted by the world make for pure worship without stain before our God and Father.”
The law of God forbids all those things that set people against each other: theft, murder, greed, etc. The positive command of God’s law is “to serve God in each other,” to walk blamelessly, do justice, and to not harm one’s fellow-man.
The codes of Israel reflect the norms of the covenant: reciprocal responsibility, mercy, and truthfulness. They embody a life in freedom from oppression: worship of the One God, rejection of idolatry, mutual respect among people, care and protection for every member of the social body. Being free and being a co-responsible community are God's intentions for us.
US Bishops, Economic Justice for All,1986: 36