I'm not sure how to explain to some of my kids why, if Jesus is Jewish, we aren't. I explained to them that Jesus came to save the Jews but they did not believe He was/is the Messiah, and they are still waiting for the coming of Christ. It still doesn't explain why He was Jewish, and we're Christian/Catholics.This is an important question, and it goes to the heart not only of the Christian understanding of the Church, but also of the way in which we interpret Scripture and salvation history. Unfortunately, in recent years, a great many misunderstandings have developed, and these have made it harder for people to understand how the Church views herself and how she views her relations to the Jewish people.
The most well known of these misunderstandings is dispensationalism, which, in a nutshell, sees the Old Covenant and the New Covenant as completely separate. In the history of Christianity, dispensationalism is a very recent idea, first put forth in the 19th century. In the United States, however, it has taken on great prominence, especially in the past 30 years, being identified with certain fundamentalist and evangelical preachers.
The widespread dissemination of dispensationalist doctrine may well play into the confusion that your students have, because it makes a stark break between Judaism and Christianity (or, more correctly, between the Old Covenant and the New). But the Church--not only Catholic and Orthodox, but mainstream Protestant communities--has historically viewed this relationship much differently.
Christ came not to abolish the Law and the Old Covenant, but to fulfill it. That is why the Catechism of the Catholic Church (para. 1964) declares that "The Old Law is a preparation for the Gospel. . . . It prophesies and presages the work of liberation from sin which will be fulfilled in Christ." Furthermore (para. 1967), "The Law of the Gospel 'fulfills,' refines, surpasses, and leads the Old Law to its perfection."
But what does this mean for the Christian interpretation of salvation history? We look back at the history of Israel with different eyes. We can see how that history was fulfilled in Christ. And we can see, too, how that history prophesied Christ--how both Moses and the Passover lamb, for instance, were images or types (symbols) of Christ.
In the same way, Israel--the Chosen People of God, whose history is documented in the Old Testament--is a type of the Church. As the Catechism of the Catholic Church notes (para. 751):
The word "Church" (Latin ecclesia, form the Greek ek-ka-lein, to "call out of") means a convocation or an assembly. . . . Ekklesia is used frequently in the Greek Old Testament for the assembly of the Chosen People before God, above all for their assembly on Mount Sinai where Israel received the Law and was established by God as his holy people. By calling itself "Church," the first community of Christian believers recognized itself as heir to that assembly.
In the Christian understanding, going back to the New Testament, the Church is the New People of God--the fulfillment of Israel, the extension of God's covenant with the Chosen People of the Old Testament to all mankind.
This is the lesson of Chapter 4 of the Gospel of John, when Christ meets the Samaritan woman at the well. Our Lord says to her, "You adore that which you know not: we adore that which we know; for salvation is of the Jews." To which she replies: "I know that the Messias cometh (who is called Christ); therefore, when he is come, he will tell us all things."
Christ is "of the Jews," but as the fulfillment of the Law and the Prophets, as the One Who completes the Old Covenant with the Chosen People and extends salvation to all who believe in Him through the New Covenant sealed in His own blood, He is not simply "Jewish," as your students put it.
And, thus, neither are we who believe in Christ. We are the spiritual heirs to Israel, the Chosen People of God of the Old Testament. We are neither completely disconnected from them, as in dispensationalism, nor do we completely replace them, in the sense that salvation is no longer open to those who were "the first to hear the Word of God" (as we say in the Prayer for the Jewish People offered on Good Friday).
Rather, in the Christian understanding, their salvation is our salvation, and thus we conclude the prayer on Good Friday with these words: "Listen to your Church as we pray that the people you first made your own may arrive at the fullness of redemption." That fullness is found in Christ, the "Alpha and Omega, the first and the last, the beginning and the end" (Revelation 22:13).
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