Sotah 38a
סוטה ל״ח א — ד"ה כִּכְתָבוֹ
Sotah 38a:1
Chachmei Bavel distinguishes between the practice outside the Temple, where priests raise their hands to shoulder height during the priestly blessing, and in the Temple, where they raise them above their heads, except the High Priest does not lift his hands above the frontplate (which bears the Tetragrammaton), though Rabbi Yehuda holds the High Priest also raises his hands above it, citing Aaron's blessing of the people.
כִּכְתָבוֹ, וּבַמְּדִינָה בְּכִינּוּיוֹ. בַּמְּדִינָה כֹּהֲנִים נוֹשְׂאִים אֶת יְדֵיהֶן כְּנֶגֶד כִּתְפֵיהֶן, וּבַמִּקְדָּשׁ עַל גַּבֵּי רָאשֵׁיהֶן. חוּץ מִכֹּהֵן גָּדוֹל, שֶׁאֵינוֹ מַגְבִּיהַּ אֶת יָדָיו לְמַעְלָה מִן הַצִּיץ. רַבִּי יְהוּדָה אוֹמֵר: אַף כֹּהֵן גָּדוֹל מַגְבִּיהַּ יָדָיו לְמַעְלָה מִן הַצִּיץ, שֶׁנֶּאֱמַר: ״וַיִּשָּׂא אַהֲרֹן אֶת יָדָיו אֶל הָעָם וַיְבָרְכֵם״.
as it is written in the Torah, i.e., the Tetragrammaton, and in the country they use its substitute name of Lordship. In the country, the priests lift their hands so they are aligned with their shoulders during the benediction. And in the Temple they lift them above their heads, except for the High Priest, who does not lift his hands above the frontplate. Since the Tetragrammaton is inscribed on it, it is inappropriate for him to lift his hands above it. Rabbi Yehuda says: Even the High Priest lifts his hands above the frontplate, as it is stated: “And Aaron lifted up his hands toward the people and blessed them” (Leviticus 9:22).
