Trypho and the true Israel: are the Christians the spiritual Israel, and were the Law and circumcision given to the Jews for the hardness of their hearts?

Justin Martyr, answered from the texts and cited to the page.

Justin Martyr answers

We are the true spiritual Israel, the descendants of Judah, Jacob, Isaac and Abraham. Abraham was approved and blessed by God in uncircumcision on account of his faith and was called the father of many nations, and we have been led to God through the crucified Christ.¹ The prophets promised a new law and a new covenant, and this is Christ himself.

Isaiah has God say of the nations, "Ask of Me, and I shall give Thee the nations for Thine inheritance." The covenant of God is not a second tablet of stone; it is Christ.² Consider Isaiah, whom you also read. He speaks of "a third Israel among the Assyrians and the Egyptians," and God calls that people His inheritance. If God blesses a people and names them Israel, how can you imagine that you alone are Israel and execrate the people God has blessed?³

Isaiah also calls Christ Himself Jacob and Israel: "Jacob is my servant, I will uphold Him; Israel is mine elect." As your nation took the name of Jacob from the one man who was surnamed Israel, so we, begotten to God by Christ, are called, and are, the true sons of God.⁴ As for the Law, I put the question to Trypho and he admitted each step, as the Scriptures compelled him.

The righteous before Moses kept none of these ordinances, and they are saved.⁵ Circumcision began with Abraham and the rest came through Moses. The sacrifices and offerings God enjoined on your fathers because of the hardness of their hearts and their tendency to idolatry, and not because He had need of them.⁶ The fringe of purple and the phylacteries were laid on you so that you would keep God before your eyes in every action.

Yet even so you were not dissuaded from idolatry. In Isaiah He rebukes you for sacrificing your children to idols. Such ordinances contribute nothing to the performance of righteousness and piety.⁷ God promised another covenant, not like the one at Horeb that was laid on your fathers with fear, trembling and lightnings. It would show which commands and deeds God knows to be eternal and fitted to every nation, and which He gave to suit the hardness of your people's hearts.⁸

The Lawgiver is present among you, and you do not see Him. You boast in the flesh and need a second circumcision, that of the heart. You keep one idle day and suppose yourselves pious. The new law requires a perpetual sabbath: let the thief cease to steal, the adulterer repent, the man with impure hands wash and be pure, and he has kept the sweet and true sabbaths of God.⁹

None of this makes the Jew an enemy, and I did not leave Trypho under a curse. If a man knows that Jesus is the Christ, believes and obeys Him, and still wishes to observe these institutions, I hold that he will be saved, provided he does not strive in every way to persuade the Gentiles that they cannot be saved unless they keep what he keeps.¹⁰ Some Christians will not receive such a man into fellowship. I do not agree with them.

The position in brief

The prophets foretold a new law and a new covenant, and these are Christ; those who come to God through the crucified Christ are the true spiritual Israel, children of Abraham by faith as Abraham was approved before he was circumcised.¹¹¹² The ceremonial Law was given because of the hardness of the people's heart, and circumcision as a sign marking them for what they now suffer; the eternal and natural righteousness binds everyone.

The Scriptures are ours because we understand them. Yet the Jew who believes and keeps the Law without imposing it is a brother, and Trypho is a friend to be prayed for.¹³¹⁴¹⁵

Sources

For the true spiritual Israel, and descendants of Judah, Jacob, Isaac, and Abraham (who in uncircumcision was approved of and blessed by God on account of his faith, and called the father of many nations), are we who have been led to God through this crucified Christ
Dialogue with Trypho
What is the covenant of God? Is it not Christ?... Ask of Me, and I shall give Thee the nations for Thine inheritance
Dialogue with Trypho
Since then God blesses this people, and calls them Israel, and declares them to be His inheritance, how is it that you repent not of the deception you practise on yourselves, as if you alone were the Israel, and of execrating the people whom God has blessed?
Dialogue with Trypho
As therefore from the one man Jacob, who was surnamed Israel, all your nation has been called Jacob and Israel; so we from Christ, who begat us unto God, like Jacob, and Israel, and Judah, and Joseph, and David, are called and are the true sons of God
Dialogue with Trypho
Are those righteous patriarchs who lived before Moses, who observed none of those [ordinances]... saved... And Trypho said, 'The Scriptures compel me to admit it.'
Dialogue with Trypho
did God enjoin your fathers to present the offerings and sacrifices because He had need of them, or because of the hardness of their hearts and tendency to idolatry?
Dialogue with Trypho
we know that the ordinances imposed by reason of the hardness of your people's hearts, contribute nothing to the performance of righteousness and of piety.
Dialogue with Trypho
it would be such as to show what kind of commands and deeds God knows to be eternal and suited to every nation, and what commandments He has given, suiting them to the hardness of your people's hearts
Dialogue with Trypho
You have now need of a second circumcision, though you glory greatly in the flesh. The new law requires you to keep perpetual sabbath, and you, because you are idle for one day, suppose you are pious
Dialogue with Trypho
such an one will be saved, if he does not strive in every way to persuade other men, --I mean those Gentiles who have been circumcised from error by Christ, to observe the same things as himself
Dialogue with Trypho
Is it not the nations? What is the covenant of God? Is it not Christ? As He says in another place: Thou art my Son; this day have I begotten Thee. Ask of Me, and I shall give Thee the nations for Thine inheritance, and the uttermost parts of the earth for Thy possession.' Chapter CXXIII.--Ridiculous interpretations of the Jews. Christians are the true Israel.
Dialogue with Trypho
For you said that, by reason of His living conformably to law, He was elected and became Christ, if indeed He were proved to be so." And Trypho said, "You admitted to us that He was both circumcised, and observed the other legal ceremonies ordained by Moses." And I replied, "I have admitted it, and do admit it: yet I have admitted that He endured all these not as if He were justified by them, but completing the…
Dialogue with Trypho
Moreover, by the works and by the attendant miracles, it is possible for all to understand that He is the new law, and the new covenant, and the expectation of those who out of every people wait for the good things of God.
Dialogue with Trypho
The reason why circumcision was given to them I stated at length in what has gone before; and if what has been said does not convince you, let us again search into the matter.
Dialogue with Trypho
But since what I have now enumerated appears to me to be sufficient, I revert again to the order of the discourse. Chapter XLIII.--He concludes that the law had an end in Christ, who was born of the Virgin.
Dialogue with Trypho

Where the argument is made

Dialogue with Trypho 11 on the new law and covenant and "the true spiritual Israel"
16 on circumcision given as a sign "that you alone may suffer that which you now justly suffer" and on "cursing in your synagogues those that believe on Christ"
18-23 and 43-46 on the Sabbath, the sacrifices and the food laws as given for the hardness of the people's heart, and on the righteous before Moses who kept none of them
29 on the Scriptures "not yours, but ours"
45 on those under the Law who did what is eternally good and are saved through Christ
46-47 on Jewish believers who keep the Law without imposing it, received "as kinsmen and brethren"
71-73 on the charge that the Jewish teachers altered and removed passages, and 43 and 66-84 on the virgin of Isaiah
80-81 on the thousand years in a rebuilt Jerusalem
119-135 on the two peoples
137 and 142 on the exhortation and the parting in friendship
First Apology 31-53 on the proof from prophecy and 47 on the desolation of Judaea

How the argument was received

The most morally charged ground in the corpus: the founding text of the Christian claim to be Israel, read now as a root of anti-Judaism, and by others as a dispute between neighbours that ends in courtesy.