Priority Given to a Levi
There is an order of priority cited in Shulchan Aruch for kibbudim (honors) such as zimum (leading the benching with a cup of wine) and aliyos (being called up to the Torah). The Kohen gets first priority, followed by the Levi, and then the Yisroel. In the case where there is no Kohen presentor if for some reason the Kohen cannot lead the bentchingthe honor is given to the Levi. Likewise, when leining (reading from the Torah) and ein kan Kohen (there is no Kohen present), the custom is to give a Levi the first aliyah. Some poskim suggest that a Levi should not get the aliyah of the Kohen so that he should not be mistaken for a Kohen. However, according to mainstream halachah a Levi should be given preference. Furthermore, many suggest that even those poskim who said that a Levi should not get the first aliyah were not of the opinion that the Levi may not get the aliyah, but only that there is no obligation to give it to him. The Alter Rebbe writes in Shulchan Aruch Harav that a special brachah of arichas yomim (blessing for longevity) is granted to one who honors a Levi by giving him priority over Yisroelimbut not over Kohanimfor zimun, leining, and in other matters. #304
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