"And Joshua did as" [Moses said to him], and so on - that which he was commanded, and he did not transgress the decree of Moses. "And Moses, Aaron, and Hur went up" - regarding the matter we have stated, to recall the deeds of the fathers and the deeds of the mothers. "And it came to pass, when Moses raised his hand" (Exodus 17:11). Now did the hands of Moses make Israel prevail, or did his hands break Amalek? Rather, as long as Moses lifted his hands toward on high, Israel would gaze upon him and believe in the One who commanded Moses to do so, and the Omnipresent would do for them miracles and mighty deeds.
When Moses Raised His Hands Israel Looked Upward in Faith
Yalkut Shimoni on Torah 264:3
וַיַּעַשׁ יְהוֹשֻׁעַ כַּאֲשֶׁר וְגוֹ', מַה שֶּׁנִּתְפַּקֵּד וְלֹא עָבַר עַל גְּזֵרַת מֹשֶׁה. וּמֹשֶׁה אַהֲרֹן וְחוּר עָלוּ. לָעִנְיַן שֶׁאָמַרְנוּ, לְהַזְכִּיר מַעֲשֶׂה אָבוֹת וּמַעֲשֶׂה אִמָּהוֹת. (שמות יז יא) וְהָיָה כַּאֲשֶׁר יָרִים מֹשֶׁה. וְכִי יָדָיו שֶׁל מֹשֶׁה מְגַבְּרוֹת אֶת יִשְׂרָאֵל אוֹ יָדָיו שׁוֹבְרוֹת אֶת עֲמָלֵק, אֶלָּא כָּל זְמַן שֶׁהָיָה מֹשֶׁה מַגְבִּיהַּ אֶת יָדָיו כְּלַפֵּי מַעְלָה הָיוּ יִשְׂרָאֵל מִסְתַּכְּלִין בּוֹ וּמַאֲמִינִים בְּמִי שֶׁפָּקַד אֶת מֹשֶׁה לַעֲשׂוֹת כֵּן, וְהַמָּקוֹם עוֹשֶה לָהֶם נִסִּים וּגְבוּרוֹת.