Jewish Believers in Jesus and the Mosaic Law: The Opinion of Justin Martyr

Justin’s attitude toward the Mosaic Law is based on three fundamental factors all of which were based on earlier Christian tradition. The first important factor was the prophetic prediction that the old Sinaitic covenant would be substituted by the new one. Jer 31:31–34 was an important key-text already used in the New Testament. Additionally, it emphasized two important topics which played a central role in the Christian theology. The new covenant was based on forgiveness, illustrating well the salvation-historical event accounted in the gospels: the death of Jesus on the cross. Another topic was a new life. According to the prophecy, the law of God would be written in the hearts of the people. Jer 31:31–34 also explains why elements of old Sinaitic covenant can be regarded as typologically corresponding to the elements of the new covenant. The Sinaitic covenant was good but after the establishment of the new covenant its meaning was mainly typological. It is also important to see that Jer 31:31–34 explains well the anthropological statement that humans are incapable of fulfilling the divine commands without help from God, i.e. that God himself puts his law on the hearts of humans.

The second factor includes many Old Testament references to the hardness of the people’s heart against listening to the word of God. This theme was developed in the Second Temple period to address the Jewish people’s unwillingness to listen to the word of God. In Christian theology this topic was developed as a reaction to the Jews’ unwillingness to accept the Christian message. Jews persisted in staying in the old Sinaitic covenant which Christians regarded as an example of hardness of their hearts. This explains why in an early Christian theology the word of Jesus that divorce was allowed by Moses because of the hardness of heart was applied to the ceremonial law. Jews do not understand that the new covenant has been established and, therefore, they want to follow old Sinaitic stipulations because of their hardness of heart.

The third topic was an apostolic tradition that Jewish believers in Jesus (“Nazoraeans”) have the right to continue to practice the Mosaic Law. Justin received all three of these topics from older Christian traditions and made a synthesis of them. This explains why there seems to be a certain tension in Justin’s theology. This becomes evident particularly in the cases when some ceremonial aspects in the Mosaic Law are seen as typoi for the coming salvation but at the same time also as expressions of the stipulations made for the hardness of the hearts of Jews. This tension was explained so that Exodus 32–34 became a hermeneutical key to understanding the stubbornness of the Jewish people. Israel received two laws: first it received Ten Commandments, and after the episode of the Golden Calf the ceremonial law because of their stubbornness.

What makes Justin’s attitude toward the Mosaic Law highly important is that he was a theologian who recognized intensive criticism toward the Jewish-Christian groups in the Church more and more, and regarded this as problematic. He was still willing to oppose those sentiments which forbad Jewish-Christian groups to practice the Mosaic Law. In this respect Justin is an important theologian who recognized that it is important for Christian theology to preserve a positive attitude toward those Jews who wanted to practice the Mosaic Law and confess that Jesus from Nazareth was the Messiah and the Son of God.