The Torah offers a release for the Jewish soldier who is far away from his home and under the strain of battle. It provides a contingency for the soldier who, in constant fear for his life, gives in to an uncontrollable desire for a beautiful captive. The soldier may marry her after she has undergone a specific process. Knowing that she will be permitted to him later may encourage him to refrain from any inappropriate advances now. While this is a special dispensation, it still should be regarded as inappropriate and even sinful. Indeed, Chazal attribute the character of the rebellious son to a union with a yefas toar, beautiful captive, in which the Jewish soldier gave in to his base desires and made use of the Torah’s dispensation. If Chazal view this action as sinful, undoubtedly it requires teshuvah, repentance.
Horav Eliyahu Schlesinger, Shlita, derives this idea from an apparent contradiction in Chazal. We are taught that Reuven is considered to be the first one to have made an “official” teshuvah. Indeed, in this merit, his descendant, Hoshea was the one to admonish Klal Yisrael with the words, “Shuvah Yisrael,” “Repent Yisrael.” He led Klal Yisrael in teshuvah. The fact that Reuven was the first to repent seems inconsistent with another Midrash that attributes this status to Kayin. Kayin told his father Adam Ha’Rishon, “I repented and came to terms with the Almighty”. Immediately, Adam responded, “This is the awesome power of teshuvah, and I was never aware of it.” How are we to reconcile these two disparate Midrashim?
Horav Schlesinger explains that Kayin repented for a sin that any human being would realize is evil. Murder is a serious crime which demands an enormous amount of teshuvah. The human conscience is such that a murderer expresses contrition as a natural reaction to the most horrendous act possible. Such a response is not a free-will action; rather, it is an automatic human response. In contrast, Reuven acted in a manner that did not really reflect evil. He easily could have justified his actions as the expression of a son jealous for his mother’s sake. It was a sin – but of a nature that most people would never recognize as a sin – and certainly would not condemn. Yet Reuven realized his error, and he proceeded to perform teshuvah. This was a truly remarkable act. He was the first person to repent for an aveirah that many might even have mistaken for a mitzvah. That response represents the highest level of teshuvah – and Reuven was the first to come to this understanding.