Thou shalt love the Lord thy God with all thy heart, and with all thy soul, and with all thy mind. This is the first and great commandment. And the second is like unto it; Thou shalt love thy neighbour as thyself. On these two commandments hang all the Law and the Prophets.
The Summary is a direct quote from St. Matthew 22:37-40. The law is an appropriate beginning to worship because it is the beginning of the Gospel. Galatians 3:24 says “The law was our tutor to bring us to Christ that we might be justified by faith.”
The law shows us that we are sinners because we have not loved God and neighbor as the law instructs us (cf. Romans 3:20 St. Matthew 6:1 7-30). The law leads us to repent and turn to Christ for forgiveness.
As we come to the altar of God we should also be mindful of our current areas of struggle and progress with regard to the law and the command to love. What particular sins are we struggling with? What particular virtues do we want to acquire? It is helpful in this regard to be familiar with the seven deadly sins: pride, anger, lust, gluttony, covetousness, envy, and sloth. These are another way of looking at the moral law. They are ways we fall short of the ideal of love. There are virtues that correspond to the deadly sins, such as humility, charity, chastity, self control, generosity, contentment, and diligence. As we pray for and practice these virtues we sin less.
The verdict of the Law leads us to ask for mercy and prepares us for the experience of redemption that follows in Word and Sacrament. Kyrie Eleison is Greek for “Lord have mercy.” It was an ancient hymn to Caesar that was adapted for Christian worship by the addition of the middle phrase “Christ have mercy upon us.” The prayer for mercy will be answered. Christ will have mercy upon us. He will forgive us and feed us with His Body and Blood.