Related for Rosh Hashanah 3:8
וְהָיָה כַּאֲשֶׁר יָרִים משֶׁה יָדוֹ וְגָבַר יִשְׂרָאֵל וְגוֹ' (שמות יז), וְכִי יָדָיו שֶׁל משֶׁה עוֹשׂוֹת מִלְחָמָה אוֹ שׁוֹבְרוֹת מִלְחָמָה. אֶלָּא לוֹמַר לְךָ, כָּל זְמַן שֶׁהָיוּ יִשְׂרָאֵל מִסְתַּכְּלִים כְּלַפֵּי מַעְלָה וּמְשַׁעְבְּדִין אֶת לִבָּם לַאֲבִיהֶם שֶׁבַּשָּׁמַיִם הָיוּ מִתְגַּבְּרִים. וְאִם לָאו, הָיוּ נוֹפְלִין. כַּיּוֹצֵא בַדָּבָר אַתָּה אוֹמֵר (במדבר כא), עֲשֵׂה לְךָ שָׂרָף וְשִׂים אֹתוֹ עַל נֵס, וְהָיָה כָּל הַנָּשׁוּךְ וְרָאָה אֹתוֹ וָחָי. וְכִי נָחָשׁ מֵמִית, אוֹ נָחָשׁ מְחַיֶּה. אֶלָּא, בִּזְמַן שֶׁיִּשְׂרָאֵל מִסְתַּכְּלִין כְּלַפֵּי מַעְלָה וּמְשַׁעְבְּדִין אֶת לִבָּם לַאֲבִיהֶן שֶׁבַּשָּׁמַיִם, הָיוּ מִתְרַפְּאִים, וְאִם לָאו, הָיוּ נִמּוֹקִים. חֵרֵשׁ, שׁוֹטֶה, וְקָטָן, אֵין מוֹצִיאִין אֶת הָרַבִּים יְדֵי חוֹבָתָן. זֶה הַכְּלָל, כֹּל שֶׁאֵינוֹ מְחֻיָּב בַּדָּבָר, אֵינוֹ מוֹצִיא אֶת הָרַבִּים יְדֵי חוֹבָתָן:
(Exodus 17:11): "And it was, when Moses lifted his hand, that Israel prevailed, etc." [Because the role of intent is discussed above, it is taught here that when one directs his heart to his Father in heaven, he prevails.] Now was it Moses' hand that made war or halted war? The intent is, rather, that so long as Israel looked on high and devoted their hearts to their Father in heaven, they were victorious; failing this, they were defeated. A parallel instance (Numbers 21:8): "Make for yourself a fiery serpent, and place it upon a pole; and it shall be, all who are bitten shall see it and live." Now does a serpent wield the power of life and death? The intent is, rather, that when Israel looked on High and devoted their hearts to their Father in heaven, they were healed; failing this, they were quashed. A deaf-mute, an imbecile, and a minor cannot effect the fulfilling of the obligation of the many. This is the rule: Whoever is not obligated in something himself cannot effect the fulfilling of the obligation of the many (therein).