אורח חיים קט״וOrach Chayim 115

Se’if 1א׳

מִפְּנֵי שֶׁמּוֹתַר הָאָדָם מִן הַבְּהֵמָה הִיא הַבִּינָה וְהַשֵּׂכֶל, קָבְעוּ בִּרְכַּת אַתָּה חוֹנֵן רֹאשׁ לָאֶמְצָעִיּוֹת, שֶׁאִם אֵין בִּינָה אֵין תְּפִלָּה.

The reason for the blessing of "Ata Chonein" ["You grace humanity with knowledge", the fourth blessing of the weekday Amidah]. Containing 1 S'if: Since humanity's advantage over animals is understanding and intellect, they established the blessing of "Ata Chonein" as the first of the [the Amidah's] middle [blessings] since if we do not have understanding, there is no [capacity for] prayer.