Vayikra 5:1 · unit 7 · Shevuos 31b

Complete Passuk

וְנֶפֶשׁ כִּי־תֶחֱטָא וְשָׁמְעָה קוֹל אָלָה וְהוּא עֵד אוֹ רָאָה אוֹ יָדָע אִם־לוֹא יַגִּיד וְנָשָׂא עֲוֺנוֹ׃

Source Citation

Torah Temimah cites Shevuos 31b.

Sefaria — Shevuos 31b
E-Daf · Shevuos 31b

Core Text — Shevuos 31b

אֶלָּא הַיְינוּ טַעְמָא דְּרַבָּנַן – דְּמַיְיתוּ לַהּ בְּקַל וָחוֹמֶר: וּמָה מִפִּי אֲחֵרִים חַיָּיב, מִפִּי עַצְמוֹ לֹא כׇּל שֶׁכֵּן?!

Rather, this is the reason of the Sages — they derive it by a kal va-chomer: if one is liable when others administer the oath, all the more so when he swears of his own accord.

A self-imposed oath of testimony that is false generates the same liability as an oath administered by others.

What Is Learned: A witness who swears on his own that he knows no testimony, when in fact he does, is liable under this verse just as one adjured by others. The kal va-chomer extends the liability of the verse to self-imposed false denials of knowledge.