When the Kohanim recite the Birkat Kohanim ("priestly blessing") in the synagogue, what is the proper way for them to position their hands and fingers?
This issue is subject to a debate between the Shulhan Aruch and the Arizal (Rabbi Yishak Luria, 1534-1572). According to the Shulhan Aruch, a Kohen should hold his fingers such that there is a total of five spaces in between them. There should be spaces between his two thumbs, between the middle finger and ring finger on each hand, and of course between the thumb and index finger on each hand. The index finger and middle finger should be held together without a space in between, as should be the ring finger and pinkie. This is the view of the Shulhan Aruch.
The Arizal, by contrast, held (based on the teachings of Kabbala) that the Kohen should leave five spaces in each hand; meaning, all the fingers should be held apart from each other, and the thumbs should similarly not touch one another. There should be a larger space between the middle finger and the ring finger than between the other fingers (except for between the index finger and thumb, which naturally has a large space), but all the fingers should be separated from one another and not touch one another. This is the view accepted by Hacham Ben Sion Abba Shaul (Israel, 1923-1998), and this is the practice that we follow.
The Shulhan Aruch and Arizal also disagree concerning the proper position of the hands during Birkat Kohanim. According to the Shulhan Aruch, the Kohanim should hold their hands such that the palms face the ground. The Arizal, however, maintained that the Kohanim should hold their hands upright, such that the palms face directly outward toward the congregation. The hands should be held opposite the head, with the right hand slightly higher than the left hand. Once again, our custom follows the position of the Arizal in this regard, unless one has a specific family Minhag to follow the other position.
Summary: When the Kohanim recite Birkat Kohanim, they should hold their hands opposite their heads and upright, with the palms facing the congregation. They should separate all the fingers from one another, leaving a larger space in between the middle finger and the ring finger, unless they have another family Minhag.
