The tradition is to designate a chair for Elijah the Prophet, the “Angel of the Covenant,” at every circumcision. The custom is that the sandek (godfather), the one holding the child on his lap during the circumcision, sits on this chair.
For thousands of years, the Jewish nation has been oppressed in many ways. When tyrannical monarchies and governments wished to attack Judaism, one of the first Divine commandments they banned was ritual circumcision.
During the regime of King Ahab (740 BCE), the Jews were forbidden from circumcising their newborn sons. Elijah the Prophet beseeched G‑d, with fervent zeal, that no rain should fall until the decree was abolished.
G‑d said to the prophet, “You always display zeal, and you have displayed zeal now… from now on, Jews will never perform a circumcision without your participation.”
For this reason, at every circumcision, we designate a chair for Elijah the Prophet often called Elijah’s Chair or Kise Eliyahu.
When the child is brought into the area where the circumcision will be performed, the mohel, the ritual circumciser, announces “kvatter,” calling the parents’ messengers to bring the infant from the mother to where the circumcision will be performed. Together, the participants welcome the child with the words, “baruch haba”-“Blessed is he who comes.”
One of the attendees is given the honor of placing the baby on the chair of Elijah ( Kise Eliyahu) as the mohel chants, “This is the seat of Elijah…” The mohel also asks that Elijah stand to his right and protect him, so nothing will go wrong during the circumcision:
This is the Seat of Elijah the Prophet, may he be remembered for good. For Your deliverance I hope, O L‑rd. I have hoped for Your deliverance, L‑rd, and I have performed Your commandments. Elijah, angel of the Covenant, here is yours before you; stand at my right and support me. I rejoice in Your word, like one who finds great spoil. Those who love Your Torah have abounding peace, and there is no stumbling for them. Happy is the man You choose and bring near to dwell in Your courtyards; we will be satiated with the goodness of Your House, Your Holy Temple.