From its beginning the Christian faith has been in conflict with the world, facing the hostility of rival religions, philosophies, and political powers. The “city of God” (as Augustine calls it) has always been at war with the “earthly city,” and that conflict, in the view of Augustine, is the dominant fact of world history. It is a struggle for the hearts of men, and it still goes on wherever Christians are found.
In the first three centuries the church encountered four chief antagonists: Judaism, philosophy, paganism, and the Roman state.
Judaism. The earliest extended account of a controversy between Christian and Jew is the Dialogue with Trypho, written by Justin Martyr not far from the year 150. Trypho was an educated Jew, perhaps identical with a Rabbi Tarphon, who is mentioned in the Jewish Mishna. Justin went about, wearing the philosopher’s cloak to mark him as a teacher, and talked of Christ as he had opportunity. He was walking one day in Ephesus when he was hailed by Trypho, who asked what was the nature of the philosophy he professed. In reply Justin gave an account of his early studies with Stoic, Pythagorean, and Platonist philosophers. Then he met an old man who was able to go beyond Plato, telling him of ancient prophets to whom God had revealed things hidden from philosophers, especially the future coming of his Son, the Christ. Justin was converted and resolved to devote his life to teaching others.
Trypho laughed when he heard the story, saying that Justin would have done better to stay with the teaching of Plato, unless he was willing fully to accept the Law and the prophets, along with observance of circumcision, the Sabbath, and the other ordinances.
Justin replied by quoting Isaiah on the calling of the Gentiles, and Jeremiah on the two covenants. Christianity, he declared, is the new covenant foretold by the prophet. It replaced the old, and it is now being preached to every people. So the discussion went on, with constant appeals to the Old Testament, which was recognized by both as a final authority. Particular emphasis is laid on the divinity of Christ, his crucifixion and resurrection, and the conversion of the Gentiles. Micah had spoken of the last days, when Jehovah should be exalted, and the nations should say: “Come ye, and let us go up to the mountain of Jehovah, and to the house of the God of Jacob, and he will teach us of his ways and we will walk in his paths. For out of Zion shall go forth the law, and the word of the Lord from Jerusalem” (Micah 4:1-7; cf. Dialogue 109). Through Micah God had made a similar prophecy. “From the rising of the sun even unto the going down of the same my name shall be great among the Gentiles, and in every place incense shall be offered unto my name, and a pure offering” (Malachi 1:10-12; cf. Dialogue 117).