St. Paul said: “To the Jews I became like a Jew… to those who are under the law, as under the law, that I might win those who are under the law; to those who are without law, as without law (not being without law toward God, but under law toward Christ)
The apostle was talking about preaching and seeing that the message of the gospel was conveyed. He is saying: the Jew believes in the Law and the Prophets. In order to convince him of the message of Christ, I speak to him as a Jew, about the Law and the Prophets, and any matters contained in them which pertain to Christ. But when it comes to the Greek, and those like them who do not have a law, who do not believe in the Bible or the Prophets, unless I speak to them in their own way. In terms that they will understand, and attract them to the faith by philosophy, I will not win them for Christ.
Likewise, if I were to speak to them about the Prophets, I would not be able to win them for Christ either.
However, the phrase: “To the Jews I became like a Jew”, doesn’t mean behaving like a Jew, for St. Paul fought against Judaization with all his might.
Some Jews who embraced Christianity wanted to introduce into it some of the Jewish beliefs and practices, such as circumcision, keeping the Sabbath and the festivals, and the lunar calendar, and all that was associated with them in terms of eating and drinking that which was lawful or unlawful, along with the rest of the Jewish rules concerning purity and unclearness. This movement was known by the name of Judaization.
St. Paul in his attacks against the Jews said: ” So let no one judge you in food or in drink, or regarding a festival or a new moon or sabbaths, which are a shadow of things to come, but the substance is of Christ. ” (Col. 2:16-17).
The words ‘in food or in drink’ here does not mean fasting, but refers to the purity or impurity of food, according to the foods that were allowed or forbidden in Judaism, but which did not apply any more under Christianity.
St. Paul preached among the Jews, just as he did among the Gentiles. In his sermon in Rome, he spoke first to the Jews. When they rejected him and became divided, he then went to the Gentiles. (Acts 28:17-29).
In order to win the Jews, he spoke in the Temple and in the Jewish synagogues, and tried to convince them of what was said in the Law and the Prophets about Christ.