Moshiach's Advocacy and the Benefit of the Doubt
Teshuvah
Rav Gedalya taught in the name of his Rebbe, Rav Yehuda Leib Mochiach of Polnoy, that Moshiach will advocate on behalf of all Klal Yisroel and give them the benefit of the doubt. He will teach their merits, even for the wicked, saying that az zay zenen girecht, that they too are tzaddikim. Through this limud zechus they will all do teshuvah, and so they will be redeemed, for "through teshuvah we will be redeemed" (Sanhedrin 97b). Rav Gedalya wrote that he received this tradition from his Rebbes and teachers. The advocacy stirs hirhurei teshuvah, thoughts of repentance and pangs of remorse, and these bring everyone to do teshuvah and become tzaddikim. Whoever advocates for all creatures and judges them favorably shares in this quality of Moshiach.
Source: Midrash Pinchas HaChodosh, p. 1; Teshuos Chen Likkutim