The Gemara in Yevamot (62b) relates the story of the death of Rabbi Akiva's talmidim. Twelve thousand pairs of his students dies during one period because they did not respect one another. The Me'iri comments that these talmidim dies between Pesach and Lag be-Omer, and for this reason it is customary not to marry during this period.
A number of questions can be raised concerning this matter. First, why does the Talmud refer to twelve thousand pairs of talmidim rather than twenty-four thousand talmidim? Second, how is it possible that Rabbi Akiva's talmidim did not have basic respect for one another? Third, why was this tragedy singled out for perpetual commemoration during the period of Sefirah? Finally, how did the custom of refraining from marriage (in contrast to other forms of aveilut which were not originally practiced) reflect the tragedy of the sefirah period?
Perhaps the answer to these questions is as follows. Although Rabbi Akiva's students were generally respectful to one another, they were deficient in one area. Each talmid had a chavrusa, a friend and study partner, with whom he would learn all day, under Rabbi Akiva's guidance. The unique relationship, which blossoms when two individuals join in the difficult and incessant challenge of attempting to master the divine law to the best of their abilities, should also produce a paramount mutual respect, far beyond the standard requirement to honor a friend. Rabbi Akiva's students lacked this lofty, but essential part of the chavrusa.
For this reason, the Gemara tells of twelve thousand pairs of talmidim, highlighting the lack of sufficient respect accorded to one member of the pair by the other. This lesson is so important that it bears constant reinforcement during sefirah, which is not only the anniversary of the tragedy, but also the period of preparation for the reacceptance of the Torah on Shavuout.
Each year during sefirah we read of the mitzvah to love one's friend as oneself (Vayikra 19:18). The obvious question is raised; how can one be expected to love every Jew as oneself? Rabbi Akiva's famous comment, cited by Rashi, that this mitzvah is a great rule in the Torah ("Ba-Torah"), also requires explanation.
The Chasam Sofer raises an additional question. The above statement of Rabbi Akiva seems to contradict his famous ruling (B.M. 62a): "Your life takes priority over your friend's." How can this be reconciled with the command to love your friend as yourself?
To answer this question, the Chasam Sofer reinterprets the word "Ba-Torah" in Rabbi Akiva's first statement. It does not mean that loving a friend is a great rule which is written in the Torah. Rather, it means that it is a great rule concerning the study of the Torah. While in the area of physical survival and attainment one's own life and possessions have priority, in the spiritual realm one must share his Torah knowledge equally with others.
Perhaps this idea can be modified in light of the above. Rabbi Akiva refers to the special chavrusa relationship which is critical to the study of Torah. while a person cannot be expected to love every Jew as he loves himself, he must love and honor his chavrusa as himself in all ways and at all times and not only while sharing Torah knowledge. Otherwise, the relationship is not a truly spiritual one, and its members are worthy of punishment for not internalizing the spirituality of Torah. In this respect, Rabbi Akiva's statement reflects the terrible tragedy of his students' death, which illustrates the importance of loving one's chavrusa as oneself and the catastrophic results of loving this command.
The Talmudic passage containing the story of Rabbi Akiva's talmidim continues and promises peace to one who loves his wife as himself and honors her more than himself. At first glance, this statement is puzzling. After all, a person is commanded to love everyone as himself. Why then is his wife singled out?
In light of the above interpretation of Rabbi Akiva's statement and the deficiency of his students, the answer is clear. Indeed, the command to love one's friend as oneself is limited to a deep spiritual relationship between two people. A man's relationship with his wife must be a spiritual one that reflects the ideals of Torah, and, as such, requires that he love her as himself, and honor her even more than himself (see Rashi). If a husband loves and honors his wife in a way which reflects his recognition of the deep spiritual nature of their relationship , he is promised peace and happiness in marriage. Otherwise, he is doomed to suffer misery and tragedy, just like Rabbi Akiva's students; they did not recognize the full measure of the spiritual nature of their relationship with one another, and as a result, did not love and honor each other sufficiently.
It is perhaps for this reason that the custom evolved to avoid marriages during the sefirah period. Since other aspects of aveilut were not practiced, the establishment of the custom to abstain from marriage was not a form of mourning for the death of Rabbi Akiva's students. Rather, it was felt that this period was not a propitious time for marriage. At a time when the true meaning of a deep one-to-one Torah relationship was ignored, it is not appropriate to begin such a relationship between husband and wife. While the command to love and honor another as oneself may be limited to one-to-one relationships, it is clear that all relationships based on Torah require mutual love and respect, commensurate with the intensity and spirit of the relationship. Let us attempt to develop appropriate levels of love and honor towards all Jews in general, and towards spouses, parents, rebbeim, and fellow talmidim in particular. In this zechut, may we merit a true commemoration of kabbalat ha-Torah and the hastening of our ultimate redemption.