Laws of Barchu
Before the blessings of Shema, the shliach tzibur (congregation leader) recites in a loud voice and in the presence of at least ten men, “Bless
It is very important to make sure to say Barchu with a minyan each day, for it is taught in Midrash Ruth that the soul does not fully settle in the body until one answers to the Barchu prayer… thus one must make an effort to pray with a minyan (Kaf HaChaim in the name of Shalmi Tzibur). It is also written in the name of the Arizal that even one who rises early to learn Torah does not fully “receive” his soul until he prays and answers to Barchu, at which point the soul settles within the person. This is the reason that the response to Barchu has five words in it — corresponding to the five names of the soul: Nefesh, Ruach, Neshama, Chaiyah and Yechida. (Kaf HaChaim)
Reciting Barchu is so important for one’s soul that it is the custom in some places to say it at the end of the morning prayers for those that missed it. We also find in the early writings (Rokeach, mentioned in the Beit Yosef) a remedy for someone who prayed without a minyan: to say a beraita of Rabbi Akiva which mentions the Barchu praise in it. One should not say it in the middle of the prayers so as not to cause an interruption. Rather, it should be said at the end of prayers before Aleinu. Yet there are some who are of the opinion that
The custom is to bow when saying Barchu, and there is a source for this in the Rishonim. However, one should not bow as deeply as is done for the Shemoneh Esrei, but rather should bow slightly. One should take care to be in the upright position when saying