Jerusalem Talmud Megillah 4.8

משנה: כֹּהֵן שֶׁיֵּשׁ בְּיָדָיו מוּמִין לֹא יִשָּא אֶת כַּפָּיו. רִבִּי יְהוּדָה אוֹמֵר אַף מִי שֶׁהָיוּ יָדָיו צְבוּעוֹת אִסַטִיס לֹא יִשָּׂא אֶת כַּפָּיו מִפְּנֵי שֶׁהָעָם מִסְתַּכְּלִין בּוֹ:

MISHNAH: A Cohen whose hands are defective shall not lift his hands. Rebbi Jehudah says, also a person whose hands are colored by woad hall not lift his hands since people look at him.

הלכה: תַּנֵּי. וּבְפָנָיו. וְהָא תַנֵּי. אִם הָיָה דָשׁ בְּעִירוֹ מוּתָּר. רִבִּי נַפְתָּלִי הַוָות אֶצְבַּעָתְיהּ עֲקִימָה. אֲתַא שְׁאִיל לְרִבִּי מָנָא. אָמַר לֵיהּ. מִכֵּיוָן שֶׁאַתָּה דָשׁ בְּעִירָךְ מוּתָּר. רַב חוּנָא הֲוָה מְעַבֵּר זַלְדָּקָן. וְהָא תַנֵּי. אִם הָיָה דָשׁ בְּעִירוֹ מוּתָּר. אָמַר רִבִּי מָנָא. רַגְלֵיהּ [הֲוֵי] סַגִּין. שֶׁלֹּא יְהוּ אוֹמְרִין. רָאִינוּ קָטָן נוֹשֵׂא אֶת כַּפָּיו. אָמַר רִבִּי יוֹסֵה. זֹאת אוֹמֶרֶת שֶׁאָסוּר לְהִסְתַּכֵּל בַּכֹּהֲנִים בַּשָּׁעָה שֶׁהֵן מְבָרְכִין אֶת יִשְׂרָאֵל. אָמַר רִבִּי חַגַּיי. כְּלוּם אָמְרוּ. אֵין מִסְתַּכְּלִין. לָא מִפְּנֵי הֶסִּיעַ דַּעַת. מֹשֶׁה. דַּאֲנָא מִסְתַּכַּלְנָא וְלָא מְסַע דַּעְתִּי.

HALAKHAH: It was stated, in his face. But was it not stated, if he was known in his town he is permitted? As the following: The finger of Rebbi Naftali was bent. He came and asked Rebbi Mana, who said to him, since you are known in your town it is permitted. Rav Ḥuna disqualified one with sparse facial hair. But was it not stated, if he was known in his town he is permitted? Rebbi Mana said, it was a crowded holiday; so they should not say, we saw a minor lifting his hands. Rebbi Yose said, this implies that one is forbidden to look at the Cohanim at the moment when they are blessing Israel. Rebbi Ḥaggai, when they said, one does not look, was it not because of inattention? By Moses, I shall look and my attention will not be diverted.