If we look for the unifying thread between the first reading and the gospel, we might call it something like “observing the Law.”
The first reading — Sirach 15:15-20 — insists that, “If you choose you can keep the commandments.” We have free will. We can’t employ the excuse, “The Devil made me do it.”This year, the weekday Mass first readings are from Genesis. We heard on Monday through Thursday of the creation on the world and of man and woman. On Friday came the story of the fall, and on Saturday, the result, with Adam blaming Eve and Eve blaming the serpent. God does not accept the excuses: all three are guilty and all three suffer the consequences. Similarly, Sirach tells us, we will experience the good or evil consequences of our good or evil choices. God knows what we do.
The responsorial psalm — verses of Psalm 119 — praises those who follow the law of the Lord and prays the we will know and obey it fully.
In the gospel — Matthew 5:17-37 — Jesus affirms the Law as valid, and tells us that our observance of it must go beyond the literal minimum. We must refrain from anger as well as murder. Of course, there are instances when we react emotionally with anger at evil, but we must not stoke that anger and hold on to it. Instead, we are to forgive and be reconciled with one another. We must refrain from lust as well as adultery. Of course we are attracted by a beautiful person, but we must not let the involuntary attraction turn to lust — which St. John Paul II says occurs when we fail to regard the person as one who has the inviolable dignity of a human person and instead make her/him an object for our own pleasure. Note also that he specifies that adultery includes marrying a divorced person unless the former marriage was invalid. Finally, we must refrain from deceptive speech as well as perjury. We should be fundamentally honest, so that it will not be necessary to put us on oath to be sure we are telling the truth.
Judaism has always regarded the Law as God’s supreme gift to Israel, something not only to be studied and observed, bit something to be joyful about. The giving of the Law proves God’s love for his people. Jesus tells us that we should take it to heart, and when we do, our observance will go beyond a literalist minimum. Our attitude won’t be “How far can I go before I’ve broken a commandment?” but, “How is God asking me to live?”
St. Paul tells us in the second reading — 1 Corinthians 2:6-10 — that God’s wisdom is far above human wisdom. God’s wisdom is aimed at providing us with a glorified existence far beyond anything we could imagine. Those who love God, as witnessed by their keeping the commandments, will receive what God has prepared — in line with Sirach’s statement that keeping the commandments will save us and trust in God will bring life. Jesus also says that we must follow the Law as he explains it if we are to enter the kingdom of heaven.