When the Kohanim come forward to the Hechal (ark) to recite Birkat Kohanim (the priestly blessing), they initially stand facing the Hechal and then turn around towards the congregation to administer the Beracha. When exactly are they to turn around to face the congregation?
The authorities are in disagreement on this issue. According to one view, the Kohanim should turn in the middle of the introductory Beracha recited before Birkat Kohanim, after the words "Asher Kodeshanu Be'mitzvotav." Others maintain that they turn to face the congregation only upon completing this Beracha, just before they begin the actual Birkat Kohanim (Rambam, Hilchot Tefliah, perek 14:12). The custom we follow is that the Kohanim turn just prior to reciting the Beracha's final word, "Be'ahava," such that they will be facing the congregation by the time they conclude the Beracha. (Hida- Birke Yosef, siman 128, s’k 9. Halacha Berura, Helek 6, page 383.)
Another debate concerns the issue of at which point the Kohanim should lift their hands. The Kohanim's hands are raised in the air during their recitation of Birkat Kohanim, but different views exist as to when precisely their arms should be lifted. The Kaf Ha'chayim Sofer in siman 128 cites the view of the Shulchan Aruch Ha'Rav (by Rabbi Shneur Zalman of Liadi, Russia, 1745-1813) that the Kohanim lift their hands only after concluding the introductory Beracha. The Shulchan Aruch Ha'Rav contended that since the recitation of the Beracha over a Mitzva always precedes the performance of the Mitzva, the Kohanim must recite the introductory Beracha before lifting their hands. However, the Kaf Ha'chayim cites the Panei'a Raza (in Parashat Naso) as requiring that the Kohanim lift their hands already when they begin reciting the introductory Beracha. He explains that since the lifting of the hands does not constitute the actual performance of the Mitzva, it need not be preceded by the recitation of the Beracha. And, from the verse in Tehillim (134:2), "Raise your hands in sanctity and bless God," it appears that one first raises his hands before reciting a Beracha. Therefore, the Kaf Ha'chayim concludes, the Kohanim should preferably lift their hands even before reciting the introductory Beracha. (See Halacha Berura, Helek 6, page 386.)
Summary: Before beginning Birkat Kohanim, the Kohanim should raise their hands while still facing the Hechal and begin reciting the introductory Beracha, and they turn around to face the congregation just before reciting the word "Be'ahava" at the end of the introductory Beracha. The Kohanim should raise their hands before reciting the introductory Beracha.
