"Do not think that I have come to abolish the law or the prophets. I have come not to abolish but to fulfill..." (Mt. 5,17)
With these words, Christ is telling us clearly that while "the law or the prophets" are not abolished, neither are they perfect. They need to be perfected or fulfilled. And their perfection and fulfillment is precisely in being vitally identified with Christ, the embodiment and spirit of the new law that is meant for us.
That's the reason why Christ says, "I am the way, and the truth, and the life. No man comes to the Father, but by me." (Jn. 14,6) And many times, he reiterated how the old law needs to be perfected.
"You have heard that it was said to your ancestors," he would say to refer to what was the norm of belief and conduct then, and then he would continue to say, "But I say to you..." This comparison is not meant to do away with the old law, which is always indispensable, but rather to go beyond it.
The old law tells us that there is a living God, that we are his creatures and more than that—that we are children of his. It tells us what is right and wrong. But it cannot bring us to God. It cannot effect our being children of his. It cannot make us do what is right and avoid what is wrong.
We need to be identified with Christ for us to be able not only to believe in God but also and more importantly to live what we believe. Our best intentions and efforts alone, without Christ, would not be enough for us to enter into the life of God. Our natural powers without the supernatural grace of God are simply incapable of reaching God.
That's why Christ gave us the new law that we have to love one another as he himself has loved us. He makes himself not only the standard or the guide, but the very substance of goodness, holiness and righteousness. His love should the very substance of our love.
And his love for his Father and for us goes all the way to offering his own life for our sins. This is the love we have to aim at and live. It is the culmination of his love for us. But before that he tells us not only to love those who love us, but also to love our enemies.
He says that while we ought not to kill, we should also avoid even getting angry with others. We should not only avoid adultery, but also we have to avoid looking at a woman with lust.
His new law of love encourages us to be unafraid of suffering if they come along our quest of that love. "If your right hand causes you to sin, cut it off and throw it away," he says. "It is better for you to lose one of your members than to have your body go into Gehenna."
This new law of love considers as blessed the poor in spirit, the meek and humble, those who hunger and thirst for justice, the persecuted, the peacemakers and clean of heart-statuses that we usually try to avoid.
This new law of love commissions us to "go and teach all nations, baptizing them in the name of the Father, and of the Son and of the Holy Spirit, and teaching them to observe all that I have commanded you." (Mt. 28,19-20)
In short, he wants us to do a continuing work of apostolate, reaching out to others and never contented with simply taking care of our own affairs and interests alone.
He assures us that he will always be with us till the end of time, and that what may appear to be pain is actually our glorification, what may be considered as loss is actually a gain.
We have to be most wary of the most deceptive kind of self-righteousness. That's when we get contented with simply following the old law, the Ten Commandments, and not going beyond them.
That self-righteousness may lead us to know a lot about what is right and wrong, but it does not prevent us from being judgmental, self-centered, vain and proud, very much attached to the things of this world-money, fame, power, etc. It's incapable of understanding others and of being merciful.
In time the falsehood of our self-righteousness will just burst into the open. It cannot pass the test of time.