כָּל־מַ֨כֵּה־נֶ֔פֶשׁ לְפִ֣י עֵדִ֔ים יִרְצַ֖ח אֶת־הָרֹצֵ֑חַ וְעֵ֣ד אֶחָ֔ד לֹא־יַעֲנֶ֥ה בְנֶ֖פֶשׁ לָמֽוּת׃
Sinumang nakapatay ng tao, ang mamamatay-tao ay papatayin batay sa patotoo ng mga saksi; ngunit ang iisang saksi ay hindi magpapatotoo laban sa isang tao upang siya ay mamatay.
Yalkut Shimoni
The requirement of testimony applies to every strike that causes injury. How do we know that it also applies to a case of exile? The verse states, "Every strike shall be according to witnesses." Just as the testimony is required for physical blows, it is also required for the case of exile. How do we know the laws of exile and corporal punishment? The verse states, "Every strike that causes injury shall be according to witnesses." This implies that the witness must be qualified to testify. How do we know that even an unqualified witness is included? The verse states, "witness and witness," which means that both a qualified and an unqualified witness are included, as "witness and witness" is mentioned to include the judge.