Mishnayos Sanhedrin Perek 3 Mishnah 8

Any time one of the litigants brings additional proof, he can overturn the verdict that was decided according to previous proofs. If one litigant said to the other: Bring all the proofs that you have from now until thirty days from now, if he found additional proof within thirty days, he can overturn the verdict. If he found it after thirty days, he cannot overturn the verdict anymore. Rabban Shimon ben Gamliel said: He can still overturn the verdict, as what should this litigant, who sought and did not find additional proof within thirty days but found it after thirty days, have done? In a case where one litigant said to the other: Bring witnesses, and the latter said: I have no witnesses, and the former said to him: Bring a proof, and he said: I have no proof, and he later brought a proof or found witnesses, in this case, this proof or these witnesses are worth nothing. It is apparently a false proof or false testimony. Rabban Shimon ben Gamliel said: What should this litigant, who did not know that he has witnesses and ultimately found witnesses, or who did not know that he has a proof and ultimately found proof, have done? Therefore, he can still overturn the verdict. If at the beginning of the discussion in the court one did not bring witnesses or other evidence for his claims, but then he saw that he was about to be deemed liable to pay in the judgment, and said: Bring so-and-so and so-and-so, and they will testify on my behalf, or he pulled out a proof from under his belt [pundato], even Rabban Shimon ben Gamliel holds that this is worth nothing. If there was truth in the testimony of these witnesses or in this proof, he would not have hidden it until now.

כָּל זְמַן שֶׁמֵּבִיא רְאָיָה, סוֹתֵר אֶת הַדִּין. אָמְרוּ לוֹ, כָּל רְאָיוֹת שֶׁיֶּשׁ לְךָ הָבֵא מִכָּאן עַד שְׁלֹשִׁים יוֹם. מָצָא בְתוֹךְ שְׁלֹשִׁים יוֹם, סוֹתֵר. לְאַחַר שְׁלֹשִׁים יוֹם, אֵינוֹ סוֹתֵר. אָמַר רַבָּן שִׁמְעוֹן בֶּן גַּמְלִיאֵל, מַה יַּעֲשֶׂה זֶה שֶׁלֹּא מָצָא בְתוֹךְ שְׁלֹשִׁים וּמָצָא לְאַחַר שְׁלֹשִׁים. אָמְרוּ לוֹ הָבֵא עֵדִים וְאָמַר אֵין לִי עֵדִים, אָמְרוּ הָבֵא רְאָיָה וְאָמַר אֵין לִי רְאָיָה, וּלְאַחַר זְמָן הֵבִיא רְאָיָה וּמָצָא עֵדִים, הֲרֵי זֶה אֵינוֹ כְלוּם. אָמַר רַבָּן שִׁמְעוֹן בֶּן גַּמְלִיאֵל, מַה יַּעֲשֶׂה זֶה שֶׁלֹּא הָיָה יוֹדֵעַ שֶׁיֶּשׁ לוֹ עֵדִים וּמָצָא עֵדִים, לֹא הָיָה יוֹדֵעַ שֶׁיֶּשׁ לוֹ רְאָיָה וּמָצָא רְאָיָה. אָמְרוּ לוֹ הָבֵא עֵדִים, אָמַר אֵין לִי עֵדִים, הָבֵא רְאָיָה וְאָמַר אֵין לִי רְאָיָה, רָאָה שֶׁמִּתְחַיֵּב בַּדִּין וְאָמַר קִרְבוּ פְּלוֹנִי וּפְלוֹנִי וְהַעִידוּנִי, אוֹ שֶׁהוֹצִיא רְאָיָה מִתּוֹךְ אֲפֻנְדָּתוֹ, הֲרֵי זֶה אֵינוֹ כְלוּם: