לֹֽא־יָקוּם֩ עֵ֨ד אֶחָ֜ד בְּאִ֗ישׁ לְכָל־עָוֺן֙ וּלְכָל־חַטָּ֔את בְּכָל־חֵ֖טְא אֲשֶׁ֣ר יֶֽחֱטָ֑א עַל־פִּ֣י ׀ שְׁנֵ֣י עֵדִ֗ים א֛וֹ עַל־פִּ֥י שְׁלֹשָֽׁה־עֵדִ֖ים יָק֥וּם דָּבָֽר׃
Satu orang saksi saja tidak dapat menjatuhkan hukuman atas seseorang karena kesalahan apa pun atau dosa apa pun, dalam pelanggaran apa pun yang dilakukannya; hanya berdasarkan keterangan dua orang saksi atau berdasarkan keterangan tiga orang saksi suatu perkara dapat ditetapkan.
Rashi
Where it cannot be demanded - [that is, where] her oath cannot [be imposed] by one witness, as is stated there: that two witnesses who saw that she secluded herself are required, which is derived from [the word] "matter" (Deuteronomy 19:15) [concerning the halakhot of monetary matters and the same word for] "matter" (Deuteronomy 24:1) [concerning the sota]. (Sotah 3b:19)
Rashi
Money, where it can be demanded - to impose an oath by [the testimony of] one witness: if he claimed a maneh, and [the defendant] denied it entirely, and one witness testifies that he is liable, he must swear, as it is stated: "A single witness may not validate against an [accused] party any guilt or blame" (Deuteronomy 19:15) -- it is for any iniquity or for any sin that he may not rise up, but he may rise up to [render one liable to] take an oath. (Shevuot 40a:10)
English Explanation of Mishnah Sotah
Scripture states, “Because he has found some unseemly matter in her” (Deuteronomy 24:1), and elsewhere [Scripture] states, “By the mouth of two witnesses ... shall the matter be established” (Deuteronomy 19:15); just as the “matter” mentioned in this latter case must be based on the testimony of two witnesses, so also here [in the case of the suspected woman] the “matter” must be based on the testimony of two witnesses. Again, the answer is a midrash. Deuteronomy 24:1 states that if a man finds in his wife “an unseemly matter”, he may divorce her. The midrash assumes that this “unseemly matter” refers to her having been secluded with the suspected other man. The word “matter” is connected with the same word used in Deuteronomy 19:15, which states that two witnesses are required in order for any “matter” to stand. The linguistic connection means that in the case of seclusion, two witnesses are required.