Mishnayos Sanhedrin Perek 5 Mishnah 4

The mishna continues: And afterward, after the court examines the first witness, they bring in the second witness and examine him. If the statements of the witnesses are found to be congruent, the court begins to deliberate the matter. They open the deliberations with an appeal to anyone who can find a reason to acquit the accused. If one of the witnesses said: I can teach a reason to acquit him, or if one of the students sitting before the judges said: I can teach a reason to deem him liable, the judges silence him, i.e., both the witness and the student. The reason is that these people are not allowed to offer information such as this. But if one of the students said: I can to teach a reason to acquit him, they raise him to the seat of the court and seat him among them, and he would not descend from there the entire day, but would sit and participate in their deliberations. If the statement of that student has substance, the court listens to him. And if even the accused says: I can teach a reason to acquit me, the court listens to him and considers his statement, provided that his statement has substance.

וְאַחַר כָּךְ מַכְנִיסִין אֶת הַשֵּׁנִי וּבוֹדְקִין אוֹתוֹ. אִם נִמְצְאוּ דִבְרֵיהֶם מְכֻוָּנִין, פּוֹתְחִין בִּזְכוּת. אָמַר אֶחָד מִן הָעֵדִים יֶשׁ לִי לְלַמֵּד עָלָיו זְכוּת, אוֹ אֶחָד מִן הַתַּלְמִידִים יֶשׁ לִי לְלַמֵּד עָלָיו חוֹבָה, מְשַׁתְּקִין אוֹתוֹ. אָמַר אֶחָד מִן הַתַּלְמִידִים יֶשׁ לִי לְלַמֵּד עָלָיו זְכוּת, מַעֲלִין אוֹתוֹ וּמוֹשִׁיבִין אוֹתוֹ בֵינֵיהֶן, וְלֹא הָיָה יוֹרֵד מִשָּׁם כָּל הַיּוֹם כֻּלּוֹ. אִם יֵשׁ מַמָּשׁ בִּדְבָרָיו, שׁוֹמְעִין לוֹ. וַאֲפִלּוּ הוּא אוֹמֵר יֶשׁ לִי לְלַמֵּד עַל עַצְמִי זְכוּת, שׁוֹמְעִין לוֹ, וּבִלְבַד שֶׁיֵּשׁ מַמָּשׁ בִּדְבָרָיו: