Our Sages, cited in the Yalkut Shim'oni, provide the missing pieces to this puzzle. Chazal explain that when Gideon asked, "If Hashem is with us, why has all this occurred", he was not merely complaining. Rather, he was fervently advocating for his brethren, invoking Hashem's mercy and compassion on their behalf. He was claiming that if our forefathers were righteous, we should be saved on their merit; if not, we should be saved all the same - just like they were saved without merit (רש"י שם).
This was precisely what Hashem had been looking for. This is the strength that Hashem spoke of. The moment Gideon exhibited advocacy for the people, Hashem declared: "It is right that I should reveal myself in My glory upon him." Thus, Hashem turned to Gideon and spoke to him directly. Hashem referred to Gideon's power of advocacy and said that this great merit of his will deliver Yisroel from their oppressors.
(ילקוט שמעוני שופטים רמז סב)
We know that in order to merit Divine revelation, one must embody holiness and purity and stand at an elevated spiritual level. This state of being is not easily attained. Even for those who are exceptionally virtuous, a series of rigorous preparations are required to create an environment where the Divine Presence can be manifest. Gideon, however, did not fit this description. In the Zohar (השמטות ב"ע רנד א"ח הזהר), he is characterized as לא זַכַּאי וְלֹא בַּר זַכַּאי - meaning he was neither righteous nor did he have righteous pedigree. Gideon originated from a family steeped in idolatry, a significant spiritual defect when it comes to the qualities expected of a divinely chosen leader.
Despite these shortcomings, this one remarkable quality allowed him to receive a revelation from the Divine, transcending the limitations of his family background and personal flaws.
Why Was the Mouth Created?
The writings of our revered Rebbes are filled with reflections on the profound importance and significance of the noble act of recognizing and bringing the merits of Klal Yisroel to the forefront. They did so themselves at every opportunity.
See the powerful words of the Kedushas Levi: הִנֵּה הַבּוֹרֵא בָּרוּךְ הוּא לֹא בָּחַר רַק בְּיִשְׂרָאֵל, לְפִיכָךְ אֵין שׁוּם אֶחָד רַשַּׁאי לוֹמַר עַל יִשְׂרָאֵל דָּבָר רָע רַק לְלַמֵּד זְכוּת עַל יִשְׂרָאֵל כְּמוֹ שֶׁכָּתוּב גַּבֵּי מָרְדֳּכַי: דּוֹרֵשׁ טוֹב לְעַמּוֹ... וְהַפֶּה לֹא נִבְרָא רַק לְדַבֵּר דִּבְרֵי תוֹרָה וּלְלַמֵּד זְכוּת עַל יִשְׂרָאֵל - The Creator, blessed is He, chose nothing but the Yidden. Consequently, no one has the right to speak ill of them. On the contrary, we must express their merits ... Our mouths were only designed to speak words of Torah and to articulate the merits of the Yidden.
(קדושת לוי בא)