It is well known that the Beit Hamikdash was destroyed because of the terrible sin of baseless hatred. We are taught that the remedy that will rebuild it is “ahavat chinam”, unconditional love. One of the most powerful expressions of this love can be found in the prayers of the Jewish People.
When one stands in prayer, he must realize that he is not alone. He stands together with all of Klal Yisrael. It is for this reason that most of the texts formulated by the Sages are in the plural. Even though the Jewish People are scattered around the world, praying in different places and at different times, all of their prayers unite as one.
The rabbis teach us that “All Jews are responsible for one another.” (Shavuot 39a) Rabbi Moshe Kordevero explains that the reason we are all responsible for each another is because spiritually all of the souls of Israel are one. Therefore, from a perspective of souls, there is a part of one’s fellow person in him, and likewise, a part of him is in his fellow person. (Tomer Devorah)
In fact, the word for “man” in Hebrew (“Adam”), which is used exclusively for the Jewish People (Yevamot 61a), has no plural form. This alludes to the aforementioned concept that all members of the Jewish People are in reality part of one collective soul. For just as many different limbs and organs make up a human body, yet they are all part of one whole organism, so too Israel is in truth one entity. Thus, even though our bodies separate one from another, our souls — which are our essence — unite us.
“You Must Love Your Fellow…”
We can now gain a deeper appreciation of the command, “You shall not stand idly by while the life of your fellow person is in jeopardy.” (Vayikra 19:16) Not everyone is in a position to help his fellow. For example, If someone is not a doctor he cannot help a sick person get well. Or someone who is not wealthy cannot help save a person from bankruptcy. So what can we do to help our fellow person in his time of need? Answer: We can pray.
In connection to this the rabbis have taught, “When I am only for myself, what am I?” (Pirkei Avot 1:14) When this teaching is applied to prayer we learn that in addition to praying for ourselves we must also pray for others. (Rabbi Yaakov Abuchatzera)