Generally speaking, the mere fact of taking part in circumcision is considered a great honor.
The role of the present is important: if they take it to heart to animate the brit-milah, they ensure the Mohel a serenity that allows him to take care of the baby in the best way. For this, they respond to the berakhot and participate by singing while waiting for the child and when he arrives, as well as when the mohel is healing the wound.
Although possible, it is not always obvious for the Mohel alone to have to take care of the baby while also having to ensure the atmosphere. I even once heard an old and competent Mohel clearly announce (“in the interests of the baby”) that if no one sang, there would be no singing because he himself was busy with something else (the brit herself). There was no singing that day!!!
Some communities are particularly distinguished by the beauty of their songs and sung poems (piyutim); this is the case for most Sephardic communities in North Africa and the East. According to Ashkenazi custom on the contrary, in principle, there are no chants at the time of the brit-milah. In this case, the Kahal will have to participate with all the more fervor to respond “amen” to the customary blessings and thus take their part in the ceremony.
(c) Eliyahu Bakish. This text is part of a book in French being prepared on the brit-milah.