Sotah7: 5
בְּרָכוֹת וּקְלָלוֹת כֵּיצַד? כֵּיוָן שֶׁעָבְרוּ יִשְׂרָאֵל אֶת הַיַּרְדֵּן וּבָאוּ אֶל הַר גְּרִיזִּים וְאֶל הַר עֵיבָל שֶׁבְּשׁוֹמְרוֹן שֶׁבְּצַד שְׁכֶם שֶׁבְּאֵצֶל אֵלוֹנֵי מוֹרֶה, שֶׁנֶּאֱמַר: ”הֲלֹא הֵמָּה בְּעֵבֶר הַיַּרְדֵּן וְגוֹ› ”, וּלְהַלָּן הוּא אוֹמֵר: ”וַיַּעֲבֹר אַבְרָם בָּאָרֶץ עַד מְקוֹם שְׁכֶם עַד אֵלוֹן מוֹרֶה”, מָה אֵלוֹן מוֹרֶה הָאָמוּר לְהַלָּן, שְׁכֶם — אַף אֵלוֹן מוֹרֶה הָאָמוּר כָּאן שְׁכֶם. שִׁשָּׁה שְׁבָטִים עָלוּ לְרֹאשׁ הַר גְּרִזִּים, וְשִׁשָּׁה שְׁבָטִים עָלוּ לְרֹאשׁ הַר עֵיבָל, וְהַכֹּהֲנִים וְהַלְוִיִּם וְהָאָרוֹן עוֹמְדִים לְמַטָּה בָאֶמְצַע. הַכֹּהֲנִים מַקִּיפִין אֶת הָאָרוֹן, וְהַלְוִיִּים אֶת הַכֹּהֲנִים, וְכָל יִשְׂרָאֵל מִכָּאן וּמִכָּאן, שֶׁנֶּאֱמַר: ”וְכָל יִשְׂרָאֵל וּזְקֵנָיו וְשֹׁטְרָיו וְשֹׁפְטָיו עֹמְדִים מִזֶּה וּמִזֶּה לָאָרוֹן וְגוֹ› ”.  הָפְכוּ פְנֵיהֶם כְּלַפֵּי הַר גְּרִזִּים וּפָתְחוּ בַבְּרָכָה: ”בָּרוּךְ הָאִישׁ אֲשֶׁר לֹא יַעֲשֶׂה פֶסֶל וּמַסֵּכָה”, וְאֵלּוּ וָאֵלּוּ עוֹנִין אָמֵן. הָפְכוּ פְנֵיהֶם כְּלַפֵּי הַר עֵיבָל וּפָתְחוּ בַקְּלָלָה: ”אָרוּר הָאִישׁ אֲשֶׁר יַעֲשֶׂה פֶסֶל וּמַסֵּכָה”, וְאֵלּוּ וָאֵלּוּ עוֹנִין אָמֵן, עַד שֶׁגּוֹמְרִין בְּרָכוֹת וּקְלָלוֹת.  וְאַחַר כָּךְ הֵבִיאוּ אֶת הָאֲבָנִים וּבָנוּ אֶת הַמִּזְבֵּחַ וְסָדוּהוּ בַּסִּיד, וְכָתְבוּ עָלָיו אֶת כָּל דִּבְרֵי הַתּוֹרָה בְּשִׁבְעִים לָשׁוֹן, שֶׁנֶּאֱמַר: ”בַּאֵר הֵיטֵב”, וְנָטְלוּ אֶת הָאֲבָנִים וּבָאוּ וְלָנוּ בִּמְקוֹמָן.
In what manner were the Blessings and the Curses [recited]? As soon as Israel crossed the Jordan they came to Mount Ger-izim and Mount Eval that are in the vicinity of Samaria near Shechem, near Elon Moreh, as it is said: Are they not across the Jordan, etc. (Deut. 11:30), and over there it states: and Abram passed through the land until the place of Shechem, until Elon Moreh (Genesis 12:6). Just as Elon Moreh there is Shechem, so Elon Moreh here is Shechem. Six tribes ascended to the top of Mount Gerizim, and six tribes ascended to the top of Mount Eval, while the Kohanim, the Leviim and the Ark stood below, in between. The Kohanim surrounded the Ark, the Leviim surrounded the Kohanim, and all of Israel were on this side and that, as it is said: And all of Israel, with its elders, its officers, and its judges, stood on this [side] and on that [side] of the Ark, etc. (Joshua 8:33).  They turned their faces toward Mount Gerizim and began with the blessing: “Blessed is the man who does not make a graven or a molten image.” And these and those responded, “Amen!” They turned their faces toward Mount Eval and began with the curse: “Cursed is the man who makes a graven or a molten image!” (Deut. 27:15). And these and those responded, “Amen!” (ibid.). [They continued in this manner] until they completed all the Blessings and Curses.  Afterward they brought the stones, [they] built an altar, plastered it with lime, and inscribed upon it all the words of the To-rah in seventy languages; as it is said: Explain [it] well (Deut. 27:8). Then they took the stones and came and spent the night in their place.