“The First Temple was destroyed because of three things; idol worship, licentiousness and the spilling of blood (murder).” After providing proof-texts that these three sins were rampant during the (latter part of the) First Temple, the Talmud (Yoma 9b) asks why, if during the Second Temple we were involved in Torah, Mitzvos and doing kindness, the Temple was destroyed then too. The Talmud’s answer? “Because there was unwarranted hatred.”
In Netzach Yisroel (4), the Maharal explains why it was specifically these sins that brought about the destruction of the Temples. G-d’s divine presence rested intensely on the First Temple, and the three sins committed during First Temple times bring about such ritual impurity (the Maharal brings proof-texts to show that this is the case) that it caused G-d’s presence to leave. During the Second Temple, the divine presence was only minimally there, but the Temple served as a unifier, as it (and specifically the altar, since offerings were not allowed to be brought anywhere else) was the center (the “heart”) of Jewish life. Therefore, when the nation’s unity was shattered by the unwarranted hatred that was pervasive then, the Temple was destroyed.
As the Maharal himself points out (in chapter 5), unity didn’t really exist during the First Temple either, as (for most of it) the nation was split into two kingdoms. Therefore, G-d’s divine presence resting on the Temple doesn’t seem to be dependant on having such unity, and it was only the ritual impurity brought about by these three sins that caused it to depart. It was only during the Second Temple, when His divine presence was not as strong, that unity was necessary for the Temple to remain intact. [True, much of the nation remained in Babylon even after the Temple was rebuilt, but they were still part of one nation, with the Temple as its nucleus, until sectarianism brought about the unwarranted hatred that became pervasive even within the traditional community (see Netziv’s introduction to B’reishis).]
Since the Third Temple, which we are anxiously awaiting, will include G-d’s divine presence resting intensely on it, if such unity is not a prerequisite for this, it cannot be said that until we remove all hatred from within us the Temple cannot be rebuilt. [Not that we shouldn`t strive for unity, nor should its importance be minimized. But unless the Third Temple must have the primary attributes of both Temples (G-d’s divine presence and national unity), the fact that the Second Temple was destroyed because of unwarranted hatred would not automatically mean that all divisiveness must be eradicated before the Third Temple can be built. For my thoughts on how to attain unity, please see https://rabbidmk.wordpress.com/2014/06/03/shavuos-5774/ . I had not seen this Maharal when I wrote that piece, but it fits very well with the notion of working to have G-d’s divine presence rest upon us being the primary unifier.]
Nevertheless, the Talmud is very clear that unwarranted hatred would have destroyed the First Temple too, had it been present. Based on its previous statement that only the Second Temple was destroyed because of unwarranted hatred, the Talmud poses a question based on a verse in Yechezkel (21:17), which is obviously talking about First Temple times (because of when Yechezkel lived and prophesied) that is understood to refer to “people who eat and drink together but speak sharply to each other as if their tongues were swords.” If such bickering existed (and it must not have been just an isolated instance, or it wouldn’t have been discussed in a verse), unwarranted hatred must have been present in the First Temple too! Although the Talmud answers that the verse is only referring to the nobility, not the vast majority of people (so unwarranted hatred did not exist then as it did during the Second Temple), the working assumption, which was not disproven, is that had unwarranted hatred existed during the First Temple, it would have been reason enough for it to have been destroyed. [This is also implied by the Talmud equating unwarranted hatred and committing the “big three” sins (idol worship, licentiousness and murder) based on the Temples being destroyed by the two; if unwarranted hatred would not have caused the destruction of the First Temple, there can be no comparison.]
It would therefore seem that having the nation divided into two kingdoms does not qualify as “unwarranted hatred.” Based on the examples described by the Talmud (eating together yet fighting with each other, and the story of Kamtza/Bar Kamtza), the expression “unwarranted hatred” (“sinas chinam”) seems to refer to people in the same social circles not getting along. If they are “eating and drinking together,” they must live in the same community and have much in common, yet they still fight with each other. Kamtza and Bar Kamtza must have been in the same social circles, or the invitation to one couldn’t have been confused as being intended for the other. Nor would Bar Kamtza have wanted so much to be at the party if it didn’t include his circle of friends too.
The Maharal asks what Kamtza did wrong, for him to also be blamed for what happened; he didn’t show up to the party because he didn’t receive an invitation! He answers that Kamtza was blamed for being close friends with someone who had an enemy, which contributes to divisiveness. The issue seems to be that Kamtza tolerated people within his social circle not getting along. Having two separate groups is not the same as having separate cliques within the same group. The former might be unfortunate; the latter can bring about destruction.
There can be two totally separate kingdoms, yet G-d’s divine presence will still dwell in the Temple. Sure, the leaders who caused such a division will be held accountable, but a division between people who live in different parts of the country, or who travel in different circles, or who remain separate because they have very different outlooks on life, is not considered “unwarranted hatred,” and will not cause the Temple to be destroyed (or prevent it from being rebuilt). Rather, it is the infighting that took place within the same groups of people that qualified as being “unwarranted,” and caused the Second Temple’s destruction. I will not attempt to define what constitutes a “group” whose infighting can prevent the Temple from being rebuilt. What I will do, though, is suggest that we don’t all have to be on the same page to be able to get along. Nor do we all have to be considered one group, thereby requiring that we resolve all of our differences. But we are required to work on our interpersonal skills, so that we can get along better with everyone, whether or not we are considered to be in the same group.