The Mitzva of זימון is very important and is often overlooked. People think that it’s part of ברכת המזון and don’t realize its significance.
Aside from being a Mitzva by itself, it is an added acknowledgement of Hashem’s bountiful blessings. Three people that sit together are not allowed to leave or “Bench” to themselves without forming this quorum known as זימון.
The leader asks the others to bless Hashem. They answer that “May Hashem’s name be blessed forever and ever.” The leader repeats this line. He asks for permission to bless Hashem for having eaten of His food. And this line is repeated by the other two members.
If ten eat together, they are able to add G-d’s holy name.
We do this ceremony all the time but rarely pause to reflect on its significance.