Riddle: Can there be something that is permitted to a Jew but prohibited to a non-Jew?
Answer: Yes. An example is the yefat to’ar (captive woman) discussed in Parshat Ki Tetzei. During war, if a Jewish soldier sees a beautiful woman (one of the enemy), he is permitted to take her captive and later marry her. How can the Torah permit such a thing? Rashi tells us that the Torah is responding to the evil inclination. In other words, “The Torah recognizes the force of the desires awakened in the violence of war. The Torah assumes that these powerful instincts will overpower many soldiers. These warriors will not be able to resist the desire to enter into sexual relations with the captive women. This creates a dilemma. Enforcement of the normal prohibition against relations with non-Jewish women would be impossible. Therefore, a strict legal framework was created for the inevitable relations. In other words, the Torah deemed it preferable for the relations to take place in this framework rather than outside of its laws” (Rabbi Bernie Fox).
The above explains how a normally forbidden sexual relationship is permitted. Doesn’t the problem of theft remain? (Kidnapping is a type of theft.) Furthermore, the law of yefat to’ar applies even to a married woman. The answer is that the permission is limited to wartime. Just as it is permitted during war to conquer territory and take the property of the enemy nation, so too it is permitted to take captives, both men and women.
However, this permission during war was given only to Jews. While non-Jews acquire property if they conquer it in war, they are not permitted to do so by Jewish law; only if they transgressed and stole property does it remains theirs. For non-Jews, even during war it is forbidden to capture property or people. For this reason, a non-Jew may not take captive a yefat to’ar (Sanhedrin 57a).
The law of yefat to’ar applies only when the enemies are non-Jews. However, in cases of civil war between Jews (as we find in the biblical book of Melachim), the dispensation of yefat to’ar does not apply, as the verse says, “when you go to war against your enemies” (Devarim 21:10). Furthermore, even if the enemies are non-Jews, if an enemy woman is captured who is halakhically Jewish (because her mother was Jewish), the dispensation of yefat to’ar does not apply.
Obviously, none of the laws of yefat to’ar apply in our times. It was relevant only for a voluntary war (declared by the king or Sanhedrin). Since we no longer have a king or Sanhedrin, we no longer engage in voluntary wars. Today’s wars are all obligatory, and a yefat to’ar is no longer permitted.