Where does the Bible forbid mixed marriages?

The Catholic Answers

It would not matter if the Bible did not forbid them. Not every detail of Christian practice is there. Christ gave the Church the power to make such legislation as she might think necessary at various times. However that God does not approve mixed marriages between people with the true religion and people without it is clear from Scripture. In the Old Testament He strictly forbade the Jews to marry outside the true religion. “If you embrace the errors of these nations that dwell among you, and make marriages with them, and join friendships . . . they shall be a pit and a snare in your way, and a stumbling block in your side .. . till He take you and destroy you from this land which He hath given you.” Joshua XXIII., 13-14. St. Paul, writing to Christians, says that a widow is free to marry, “but,” he adds, “let her marry in the Lord.” 1 Cor. VII., 39. In dealing with marriage in general, he writes to the Ephesians, “But I speak in Christ and in the Church.” Eph. V., 32. He gives the solemn warning as regards marriage with unbelievers, “How knowest thou, 0 wife, whether thou shalt save thy husband? Or how knowest thou, O man, whether thou shalt save thy wife?” 1 Cor. VII., 16.

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