Justin does not content himself with the exposition of a Christian interpretation of the Bible. He often denounces the Jews for having crucified Jesus, and he accuses them of continuing to persecute Christians. He finds many indications that God had deemed the Jews as especially reprehensible. In repudiating the efficacy of the law as prescribed in the Bible, Justin makes the bold assertion that the law was initially given to the Jews because, as an especially unspiritual race, hard-hearted, rebellious, and ungodly, they needed a more elaborate law, with many more disciplines as a means of mitigating some of their offensive qualities. For the gentiles, however, it was enough to prescribe two commandments as Jesus did, the love of God and the love of man (Dial. 93:4).

Justin also makes himself into a philosopher of history and offers the theory that the defeats of the Jews in the wars against Rome, both in the year 70, and again in 135, were God's visitation of a deserved punishment, because they had sinned so grievously by crucifying Christ and rejecting his new faith. Justin gloated as he contemplated the destruction of Jerusalem and the collapse of the Jewish struggle for freedom, and he taunted Trypho with this sweeping assertion: "All this has happened to you rightly and well, For ye slew the Just One and His prophets before Him, and now ye reject, and … dishonor those who set their hopes on Him, and God Almighty and Maker of the universe who sent Him …" (Dial. 16:3–4).

Justin's invective against Jews and Judaism entered the mainstream of Christian thought and became a sinister influence which contributed not a little toward the development of what is known as Christian antisemitism.

He makes the claim that Christianity is the authentic flowering of biblical
Judaism, and that the Jews who cling to their faith in its old form are clinging
to an obsolete doctrine. For doing so they are berated as blind and stubborn and
insensitive, a fossil people clinging to a superseded faith.