Washing the Hands of the Kohen

The Kohen is required to ritually wash and sanctify his hands before Birkat Kohanim. The al netilat yadayim blessing is not recited after this hand-washing. The hands should be washed in the closest possible time-proximity to the Birkat Kohanim (typically after the Kedushah is recited in the Repetition of the Amidah).

G‑d conferred upon the holy tribe of Levi the privilege of assisting and serving the Kohanim while they are in the "line of duty." Thus the honor of washing the Kohanim's hands belongs to the Levites. If no Levite is present, a firstborn son does the honors. (Although the priesthood was removed from the firstborn following the Golden Calf debacle, they still retain an added measure of holiness.) If no Levite or firstborn is in attendance, the Kohen should wash his own hands.

Before washing the Kohen's hands, the Levite (or firstborn) should wash his own hands. Chabad custom is for the Levite to wash his hands three times intermittently—as one does after waking in the morning. Conversely, the Kohen's hands are washed as is customary when washing for bread—right hand three times and then left hand three times.

The Kohen should not speak between the hand-washing and the Birkat Kohanim.

Removal of Shoes

The Kohen removes his shoes before the Birkat Kohanim. The shoe removal prevents the congregation from snickering at a Kohen who, happening to have a torn shoelace, remains behind to fix the lace, and refrains from joining his Kohen brethren.

The Kohen should remove his shoes before washing his hands, or at the very least loosen or untie his shoelaces so that he needn't touch his shoes afterwards to remove them, since this would obligate him to rewash his hands.

Out of respect for the congregation, the shoes should not be strewn in the synagogue aisles. Instead, they should be neatly tucked out of sight, beneath a chair or table, for the duration of the blessing.

Moments before the Blessing

The chazzan beginning the Retzay blessing is the cue for the Kohanim to rise and make their way to the front of the sanctuary (all hands should be washed before this point). The Kohanim must start making their way to the front of the sanctuary when the chazzan begins this blessing. If, for some reason, a Kohen has not left his place by the time the chazzan ends the blessing of Retzay, he can no longer administer the priestly blessing, and should instead leave the sanctuary for the duration of the blessing.1 In many communities (though not in Chabad congregations), a brief prayer — recited only when the Kohanim administer the Priestly Blessing — is recited by both chazzan and congregation in middle of the Retzay blessing, starting with the words Vite'arev lifanecha.

The Kohanim stand in front of the congregation facing the Holy Ark. In the interim moments, after reciting the "Rabanan Modim" with the congregation, the Kohen silently recites a short prayer (found in the prayer book) beseeching G‑d that the forthcoming blessing be "a perfect blessing; that it should have no impediment or iniquity…" Ideally, the Kohen should conclude this blessing as the chazzan finishes the Modim blessing—allowing the congregation to respond "Amen" to both prayers simultaneously.

The Kohen then covers his head and upper body with his tallit and awaits the start of the Birkat Kohanim.