An allergy is an overreaction of the immune system. A relatively minor, harmless stimulus, such as a speck of dust or a grain of pollen, is misidentified as a danger to the system, and the body gears up for battle as if it is fighting off a deadly infection. Symptoms of allergy can include a skin rash, itching, tearing eyes, and even swelling of the airways and circulatory shock.

Sometimes the immune system turns against the body itself, launching an attack against a particular organ. The same antibodies that normally protect the body against viruses and bacteria start to invade a body part and cause disease. Illnesses such as hepatitis, arthritis, and diabetes can all be caused by autoimmunity.

Like all matters in the physical world, the concept of autoimmunity also has a spiritual counterpart: When we overreact and attack someone who actually is a part of us, a brother or a sister. When we harm someone else, we are doing harm to ourselves, in a completely illogical manner.

This is true of most family feuds, as well as the political battles that erupt between various factions in Judaism. This is by no means a new phenomenon. The leading cause of the destruction of the Holy Temple in Jerusalem was "autoimmunity" -- the senseless hatred between brothers.

The teachings of Chassidut explain that no nation has the power to harm the Jewish people, because we are the chosen nation of G-d. Only when we  weaken ourselves through internal battles, are the non-Jews able to overcome us.

The third Temple, which will be rebuilt with the coming of Moshiach, will last forever. It will be an expression of our selfless love for each other, even for those who appear different from ourselves, who do not share views, beliefs or practices. A house built on the strength of this love will never be destroyed. The G-dliness within every Jew will be revealed and we will not be torn apart again.

The Lubavitcher Rebbe has taught that by virtue of the love we have shown to one another over the course of exile, we have already corrected the cause of the destruction. There is nothing holding back the Redemption. There may be some remnants of evil left, trying to sow discord and strife, but the hatred is in its death throes and will soon be eradicated completely.

Our task now is to begin to live with the type of love and harmony we will experience in the era of Redemption. Instead of developing antibodies to each other, we need to develop "pro-bodies" -- to constantly look for the good in the other person and try to strengthen and encourage him in any possible way. This is sure to bring about the ultimate Redemption.