“Do not think that I have come to abolish the law and the prophets; I have come not to abolish them but to fulfill [Greek: plerosai] them” Mt 5:17.
Rabbi Matityahu’s Greek word plerosai, and its “dictionary form” pleroo, mean “to make complete.” God’s National Revelation revealed through Rabbi Yeshua, the New Moses, completes his National Revelation revealed through Moses.
§ 581 “In Jesus, the same Word of God that had resounded on Mount Sinai to give the written Law to Moses, made itself heard anew on the Mount of the Beatitudes. Jesus did not abolish the Law but fulfilled it by giving its ultimate interpretation in a divine way: ‘You have heard that it was said to the men of old … But I say to you …” Mt 5:33–34.
Rabbi Yeshua’s fulfillment is the accomplishment of something promised, the acquisition of something hoped for. All of the 613 Torah mitzvot taken together point toward, and were fulfilled by, Rabbi Yeshua’s law:
“You shall love the Lord your God with all your heart, and with all your soul, and with all your mind. This is the great and first commandment. And a second is like it, You shall love your neighbor as yourself. On these two commandments depend all the law and the prophets” Mt 22:37–40.
Rabbi Yeshua had said, “Think not that I have come to abolish the law and the prophets; I have come not to abolish them but to fulfill them. For truly, I say to you, till heaven and earth pass away, not an iota, not a dot, will pass from the law until all is accomplished” Mt 5:17–18.
He explained the fulfillment. “You shall love the Lord your God with all your heart, and with all your soul, and with all your mind. This is the great and first commandment. And a second is like it, You shall love your neighbor as yourself. On these two commandments depend all the law and the prophets” Mt 22:37–40.
Rabbi Yeshua’s “On these two commandments depend all the law and the prophets” Mt 22:40 means that the entire Torah, and all the Jewish canon of Scripture, are fulfilled in this: “Completely detach yourself from material possessions and attach yourself instead to the Son of God, Rabbi Yeshua, who teaches love for God (the first three Commandments) and love for neighbor (the remaining seven.)
Rabbi Yeshua’s charism for Infallible teaching Mt 16:18 enables the Catholic Church to teach Infallibly on only these two subjects, how we love God (faith) and how we love one another (morals).
Mark Shea: What Does It Mean to Say Jesus has Fulfilled the Old Covenant?