Mishnayos Shevuos Perek 5 Mishnah 2

The mishna continues: What is the case of an oath on a deposit? It is where the claimant said to the defendant: Give me my deposit, which is in your possession, and the defendant replied: On my oath nothing of yours is in my possession; or the defendant said to him: Nothing of yours is in my possession, the claimant responded: I administer an oath to you, and the defendant said: Amen. In either case this defendant is liable to bring a guilt-offering if he lied. If the claimant administered an oath to him five times, whether in the presence of a court or not in the presence of a court, and the defendant falsely denied each claim, he is liable to bring a guilt-offering for each and every denial. Rabbi Shimon said: What is the reason? It is due to the fact that he is able to retract and confess after each oath and repay the claimant. Since he did not do so, each oath is considered a separate denial of a monetary claim.

שְׁבוּעַת הַפִּקָּדוֹן כֵּיצַד. אָמַר לוֹ, תֶּן לִי פִקְדוֹנִי שֶׁיֵּשׁ לִי בְיָדֶךָ, שְׁבוּעָה שֶׁאֵין לְךָ בְיָדִי, אוֹ שֶׁאָמַר לוֹ אֵין לְךָ בְיָדִי, מַשְׁבִּיעֲךָ אָנִי, וְאָמַר אָמֵן, הֲרֵי זֶה חַיָּב. הִשְׁבִּיעַ עָלָיו חֲמִשָּׁה פְעָמִים, בֵּין בִּפְנֵי בֵית דִּין וּבֵין שֶׁלֹּא בִּפְנֵי בֵית דִּין, וְכָפַר, חַיָּב עַל כָּל אַחַת וְאֶחָת. אָמַר רַבִּי שִׁמְעוֹן, מַה טַּעַם, מִפְּנֵי שֶׁיָּכוֹל לַחֲזֹר וּלְהוֹדוֹת: