+ Mt 5: 17-19
“Do not think that I have come to abolish the law or the prophets. I have come not to abolish but to fulfill.
Amen, I say to you, until heaven and earth pass away, not the smallest letter or the smallest part of a letter will pass from the law, until all things have taken place.
Therefore, whoever breaks one of the least of these commandments and teaches others to do so will be called least in the kingdom of heaven. But whoever obeys and teaches these commandments will be called greatest in the kingdom of heaven.
The New American Bible
The Catechism of the Catholic Church
592 Jesus did not abolish the Law of Sinai, but rather fulfilled it (cf. Mt 5:17-19) with such perfection (cf. Jn 8:46) that he revealed its ultimate meaning (cf.: Mt 5:33) and redeemed the transgressions against it (cf. Heb 9:15).
1967 The Law of the Gospel “fulfills,” refines, surpasses, and leads the Old Law to its perfection. In the Beatitudes, the New Law fulfills the divine promises by elevating and orienting them toward the “kingdom of heaven.” It is addressed to those open to accepting this new hope with faith – the poor, the humble, the afflicted, the pure of heart, those persecuted on account of Christ and so marks out the surprising ways of the Kingdom.