The night before the Bris is called "Leil Shimurim," or in Yiddish, "Vach Nacht" -- the night of vigil. Jewish mystical teachings explain that because the mitzvah of Brit
Milah is so great and spiritually powerful, negative spiritual forces are at
work to hinder the performance of this mitzvah. Therefore, one must take
positive action during the night before the Brit to serve as a spiritual
protection.
A beautiful tradition passed down through the generations is the custom of inviting children to come to the home of the newborn on the night before the Brit to pray, recite Psalms, and make blessings
over food. Children's voices are pure and their souls are
unblemished. Their prayers pierce the heavens, forming a spiritual shield
and drawing down blessings upon the newborn and the entire household.
The following are some of the prayers traditionally recited by the children in the presence of the newborn:
Hear O Israel, the Lord is our God,
the Lord is One.
Blessed be the name of the glory of His kingdom forever and ever.
You shall love the Lord your God
with all your heart, with all your soul, and with all your might. And these
words which I command you today shall be upon your heart. You shall teach them
thoroughly to your children, and you shall speak of them when you sit in your
house and when you walk on the road, when you lie down and when you rise. You
shall bind them as a sign upon your hand, and they shall be for a reminder
between your eyes. And you shall write them, upon the doorposts of your house and upon your
gates.
May the angel who has delivered me from all evil bless the lads, and may my name
and the name of my fathers Abraham and Isaac be called upon them, and may they
increase abundantly like fish in the midst of the earth.
During this night, the father devotes himself to Torah study, ideally near
the child. Some material has been provided here.
It is also appropriate to keep some light on in the child's room throughout the night.